K2KARAKORAM
मराठीEnglish
Open the app

State Board · Class 7 · Mathematics

Lesson 10: Banks and Simple Interest

5 concepts · 40 practice questions with answers · Free to read

This lesson is also in: मराठी

Bank accounts

From daily life

Money kept at home can get lost. If it is kept in a bank it stays safe, and in some accounts it even earns a little extra money.

Simple definition

The record that a bank keeps for the money we put in it is an account. Money kept for a fixed time is a deposit, and the extra money the bank pays on it is interest.

0Current30Savings60Recurring70Fixed

In the figure: If 1000 rupees are kept for 1 year, the interest (example numbers chosen for understanding) is 0 in a current account, 30 in a savings account, 60 in a recurring deposit and 70 in a fixed deposit.

Rule 1: A current account is for daily dealings, a savings account is for saving — A person who has to put in and take out money many times a day finds a current account convenient; it pays no interest. For saving we use a savings account; it pays a little interest.

  • Easy: A vegetable seller has to put in and take out money many times a day. A current account suits her.
  • Medium: A student saves pocket money and wants a little interest. A savings account suits the student. As in the figure, 1000 rupees earn 30 rupees in a savings account and 0 in a current account.
  • Exam type: By the numbers in the figure, how many rupees more interest does a savings account give than a current account? 30 − 0 = 30 rupees.
Fixed deposit12000Recurring deposit1000 × 12 = 12000

In the figure: In the fixed deposit 12000 rupees are put in at once. In the recurring deposit 1000 rupees are paid every month for 12 months, that is 1000 × 12 = 12000. The total paid is the same in both.

Rule 2: In a recurring deposit the same amount is paid every month; in a fixed deposit the whole amount is put in at once — A recurring deposit means paying the same amount every month for a fixed number of months; total = monthly amount × months. A fixed deposit means putting the whole amount in at once for a fixed time.

  • Easy: 500 rupees a month for 12 months. Total = 500 × 12 = 6000 rupees.
  • Medium: 800 rupees a month for 9 months. Total = 800 × 9 = 7200 rupees.
  • Exam type: A total of 24000 rupees is to be paid equally over 12 months. Monthly amount = 24000 ÷ 12 = 2000 rupees.

Rule 3: A joint account has two or more persons; use the ways of taking out money safely — A joint account is in the names of two or more persons, for example mother and father. Money is taken out with a cheque, a withdrawal slip or an ATM card. The secret number (PIN) of a card must never be told to anyone.

  • Easy: An account in the names of mother and father is a joint account.
  • Medium: Two sisters put 1200 and 2800 rupees in a joint account. Total = 1200 + 2800 = 4000 rupees.
  • Exam type: Meera told her card PIN to a friend. This is wrong, because a person who knows the PIN can take her money out.
Live figure

Bank accounts

In the app you can move this figure with your finger.

Open in the app
Remember

A current account is for daily dealings, a savings account for saving, and recurring and fixed deposits are for a fixed time. In the figure the interest rises as 0, 30, 60, 70.

Common mistake

Thinking that the whole amount must be paid at once in a recurring deposit. In a recurring deposit 1000 rupees are paid every month; in 12 months the total is 12000.

Shortcut

Total in a recurring deposit = monthly amount × months. Conversely, monthly amount = total ÷ months.

Spot the difference

PointRecurring depositFixed deposit
How the money is paidThe same amount every monthAll at the start
Number of payments in the figure121
Total amount in the figure1200012000
Who it suitsA person with a monthly incomeA person who has a lump sum

Practice questions

Easy
  1. 1600 rupees a month were paid into a recurring deposit for 10 months. What is the total paid?
  2. 2A shop puts in and takes out money many times a day. Which suits it, a current account or a savings account?
  3. 3By the numbers in the figure, how many rupees more interest does a fixed deposit give than a savings account?
Medium
  1. 4A total of 9600 rupees is to be paid into a recurring deposit over 12 months. How much should be paid each month?
  2. 5450 rupees a month were paid for 8 months. What is the total?
  3. 6Priya paid 1000 rupees a month into a recurring deposit for 6 months. Dev put 6000 rupees at once into a fixed deposit. Whose total paid is more?
Challenging
  1. 7A total of 18000 rupees is to be paid into a recurring deposit over 15 months. How much should be paid each month?
  2. 8Sana paid 900 rupees a month into a recurring deposit for 10 months and put 4000 rupees into a fixed deposit. How much did she pay in all?
Show answers (try them yourself first)
  1. 1Total = 600 × 10 = 6000 rupees.
  2. 2A shop has many dealings, so a current account suits it. 3) 70 − 30 = 40 rupees.
  3. 4Monthly amount = 9600 ÷ 12 = 800 rupees.
  4. 5Total = 450 × 8 = 3600 rupees.
  5. 6Priya: 1000 × 6 = 6000 rupees. Dev: 6000 rupees. The two totals are equal.
  6. 7Monthly amount = 18000 ÷ 15 = 1200 rupees.
  7. 8Recurring deposit: 900 × 10 = 9000. Total = 9000 + 4000 = 13000 rupees.

Passbook entries

From daily life

A passbook is the notebook of our bank account. One line is written when money is put in, another when money is taken out, and the last column shows how much is left.

Simple definition

The money put into the account is the deposit, the money taken out is the withdrawal, and the money left in the account is the balance. The bank also adds interest to the account.

DetailsOutInBalance4000cash25006500cheque18004700cheque9005600self6005000interest755075

In the figure: The opening balance is 4000. After a deposit of 2500 it is 6500. A withdrawal of 1800 makes it 4700. After a deposit of 900 it is 5600. A withdrawal of 600 makes it 5000. At the end interest of 75 is added and the balance is 5075.

Rule 1: New balance = old balance + deposit − withdrawal — In every line of the passbook the deposit is added to the old balance and the withdrawal is subtracted.

  • Easy: Balance 2000 rupees and a deposit of 800 rupees. New balance = 2000 + 800 = 2800 rupees.
  • Medium: Balance 5000 rupees. 1200 rupees are deposited and 700 rupees are withdrawn. New balance = 5000 + 1200 − 700 = 5500 rupees.
  • Exam type: Balance 6400 rupees. 2700 rupees are deposited and 3100 rupees are withdrawn. New balance = 6400 + 2700 − 3100 = 6000 rupees.

Rule 2: The money withdrawn cannot be more than the balance in the account — The bank does not pay more money than there is in the account. So look at the balance before taking money out.

  • Easy: The balance is 2000 rupees and 2500 rupees are to be taken out. 2500 is more than 2000, so this is not possible.
  • Medium: Balance 4800 rupees, then 700 rupees are deposited: 4800 + 700 = 5500. Now 5600 rupees cannot be taken out, because 5600 is more than 5500.
  • Exam type: Balance 8200 rupees. First 6000 rupees are taken out: 8200 − 6000 = 2200. Now 2500 rupees are to be taken out; that is not possible, because 2500 is more than 2200.
4000+3475−24004000 + 3475 − 2400 = 50752500 + 900 + 75 = 34751800 + 600 = 2400

In the figure: The opening balance is 4000. All deposits 2500 + 900 + 75 = 3475. All withdrawals 1800 + 600 = 2400. The closing balance is 4000 + 3475 − 2400 = 5075.

Rule 3: Closing balance = opening balance + all deposits − all withdrawals — Interest is also money that comes into the account. Adding all the deposits together and all the withdrawals together gives the same answer.

  • Easy: Opening balance 1000. Deposit 500 and withdrawal 300. Closing balance = 1000 + 500 − 300 = 1200 rupees.
  • Medium: Opening balance 8000 rupees. The bank adds interest of 120 rupees. Closing balance = 8000 + 120 = 8120 rupees.
  • Exam type: Opening balance 6000. Deposits 1300 and 2100. Withdrawals 900 and 1600. Closing balance = 6000 + (1300 + 2100) − (900 + 1600) = 6000 + 3400 − 2500 = 6900 rupees.
Live figure

Passbook entries

In the app you can move this figure with your finger.

Open in the app
Remember

New balance = old balance + deposit − withdrawal. In the figure the balance of 4000 became 4000 + 3475 − 2400 = 5075.

Common mistake

Adding the withdrawal and subtracting the deposit. The amount in the deposit column is added; the amount in the withdrawal column is subtracted.

Shortcut

To check the answer: closing balance = opening balance + all deposits − all withdrawals. In the figure it comes to 5075 again.

Spot the difference

PointDepositWithdrawal
Where the money goesComes into the accountGoes out of the account
Effect on the balanceThe balance risesThe balance falls
First deposit and first withdrawal in the figure25001800
LimitNo limitNot more than the balance

Practice questions

Easy
  1. 1The balance is 3000 rupees and 1200 rupees are deposited. What is the new balance?
  2. 2The balance is 5600 rupees and 1600 rupees are withdrawn. What is the new balance?
  3. 3The balance is 7000 rupees and the bank adds interest of 140 rupees. What is the new balance?
Medium
  1. 4The balance is 6000 rupees. 2500 rupees are deposited and 1500 rupees are withdrawn. What is the closing balance?
  2. 5The balance is 4000 rupees. 3000 rupees are deposited and 1300 rupees are withdrawn. What is the closing balance?
  3. 6The balance is 2000 rupees. Can 2500 rupees be taken out?
Challenging
  1. 7The opening balance is 10000 rupees. Interest of 890 rupees is added and 5700 rupees are withdrawn. What is the closing balance?
  2. 8The opening balance is 9000 rupees. First 4000 rupees are withdrawn and then 2500 rupees are deposited. What is the closing balance?
Show answers (try them yourself first)
  1. 13000 + 1200 = 4200 rupees.
  2. 25600 − 1600 = 4000 rupees. 3) 7000 + 140 = 7140 rupees.
  3. 46000 + 2500 − 1500 = 7000 rupees.
  4. 54000 + 3000 − 1300 = 5700 rupees.
  5. 6No, because 2500 is more than 2000.
  6. 710000 + 890 − 5700 = 5190 rupees.
  7. 89000 − 4000 = 5000. 5000 + 2500 = 7500 rupees.

Simple interest

From daily life

When we keep money in a bank, the bank uses it and pays us a little extra for it. When we take a loan, we pay back a little extra. This extra money is interest.

Simple definition

The money deposited or borrowed is the principal. The interest on 100 rupees in 1 year is the rate; for example rate 6 means 6 rupees a year on every 100 rupees. Interest counted every year only on the original principal is simple interest.

10061626318

In the figure: Every 100 rupees bring 6 rupees each year. Over years 1, 2 and 3 the interest adds up to 6 + 6 + 6 = 18 rupees.

Rule 1: The rate is the interest on 100 rupees in 1 year — If the rate is 5, then 100 rupees earn 5 rupees in a year. If the years increase, the interest increases by that many times.

  • Easy: Rate 5, principal 100 rupees. Interest for 1 year is 5 rupees. Interest for 3 years = 5 × 3 = 15 rupees.
  • Medium: Rate 5, principal 200 rupees. 200 has 2 groups of 100. Interest for 1 year = 2 × 5 = 10 rupees.
  • Exam type: Rate 4, principal 700 rupees. There are 7 groups of 100. Interest for 1 year = 7 × 4 = 28 rupees. Interest for 2 years = 28 × 2 = 56 rupees.
400040÷ 100200× 5600× 3

In the figure: The principal is 4000 rupees. 4000 ÷ 100 = 40, that is 40 groups of 100. With rate 5, the interest for 1 year is 40 × 5 = 200 rupees. The interest for 3 years is 200 × 3 = 600 rupees.

Rule 2: Interest = (principal ÷ 100) × rate × years — First count the groups of 100 in the principal, then multiply by the rate, then by the years.

  • Easy: Principal 3000, rate 6, 1 year. 3000 ÷ 100 = 30. Interest = 30 × 6 = 180 rupees.
  • Medium: Principal 5000, rate 8, 3 years. 5000 ÷ 100 = 50. 50 × 8 = 400. Interest = 400 × 3 = 1200 rupees.
  • Exam type: Principal 12000, rate 7, 4 years. 12000 ÷ 100 = 120. 120 × 7 = 840. Interest = 840 × 4 = 3360 rupees.
2000 × 7.5 = 1500015000 × 2 = 3000030000 ÷ 100 = 300

In the figure: Principal 2000, rate 7.5, years 2. First 2000 × 7.5 = 15000. Then 15000 × 2 = 30000. Finally 30000 ÷ 100 = 300 rupees of interest.

Rule 3: Interest = principal × rate × years ÷ 100 — Multiply the three numbers together and divide by 100 at the end. The answer is the same.

  • Easy: Principal 2000, rate 5, 2 years. 2000 × 5 = 10000. 10000 × 2 = 20000. 20000 ÷ 100 = 200 rupees.
  • Medium: Principal 7500, rate 4, 3 years. 7500 × 4 = 30000. 30000 × 3 = 90000. 90000 ÷ 100 = 900 rupees.
  • Exam type: Principal 36000, rate 9, 4 years. 36000 × 9 = 324000. 324000 × 4 = 1296000. 1296000 ÷ 100 = 12960 rupees.
Live figure

Simple interest

In the app you can move this figure with your finger.

Open in the app
Remember

Interest = principal × rate × years ÷ 100. In the figure, 2000 × 7.5 × 2 ÷ 100 = 300.

Common mistake

Forgetting to divide by 100 at the end. Then the interest comes out far bigger than the principal, which shows a mistake.

Shortcut

First find the interest for 1 year, then multiply by the years. In the figure the interest for 1 year is 200 and for 3 years 600.

Spot the difference

PointPrincipalInterest
What it isThe original money deposited or borrowedThe extra money earned or paid
Value in the figure4000600
If the years increaseStays the sameGrows by the same 200 every year
How it is foundIt is givenPrincipal × rate × years ÷ 100

Practice questions

Easy
  1. 1Principal 1000 rupees, rate 4, 2 years. What is the interest?
  2. 2Principal 5000 rupees, rate 6, 1 year. What is the interest?
  3. 3Principal 1200 rupees, rate 3, 1 year. What is the interest?
Medium
  1. 4Principal 8000 rupees, rate 5, 6 years. What is the interest?
  2. 5Principal 4500 rupees, rate 6, 5 years. What is the interest?
  3. 6Principal 6000 rupees, rate 7.5, 2 years. What is the interest?
Challenging
  1. 7The interest for 1 year is 480 rupees. What is the interest for 5 years?
  2. 8Find the interest on 8000 rupees at rate 5 for 4 years and for 3 years. What is the difference between them?
Show answers (try them yourself first)
  1. 11000 × 4 × 2 ÷ 100 = 80 rupees.
  2. 25000 × 6 ÷ 100 = 300 rupees. 3) 1200 × 3 ÷ 100 = 36 rupees.
  3. 48000 × 5 × 6 ÷ 100 = 2400 rupees.
  4. 54500 × 6 × 5 ÷ 100 = 1350 rupees.
  5. 66000 × 7.5 × 2 ÷ 100 = 900 rupees.
  6. 7480 × 5 = 2400 rupees.
  7. 84 years: 8000 × 5 × 4 ÷ 100 = 1600. 3 years: 8000 × 5 × 3 ÷ 100 = 1200. Difference = 1600 − 1200 = 400 rupees.

Total amount

From daily life

When a deposit ends, the bank returns both our original money and the interest on it. When we repay a loan, we also pay the original sum and the interest. This total money is called the amount.

Simple definition

The sum of the principal and the interest is the amount. It is the total money that there is at the end, principal and interest together.

6000900PrincipalInterest6900

In the figure: The principal is 6000 rupees and the interest is 900 rupees (rate 5, 3 years). The amount is 6000 + 900 = 6900 rupees.

Rule 1: Amount = principal + interest — First find the interest, then add it to the principal. Conversely, interest = amount − principal.

  • Easy: Principal 4000 rupees, interest 600 rupees. Amount = 4000 + 600 = 4600 rupees.
  • Medium: Principal 8000 rupees, interest 800 rupees. Amount = 8000 + 800 = 8800 rupees.
  • Exam type: Principal 15000, rate 6, 4 years. Interest = 15000 × 6 × 4 ÷ 100 = 3600. Amount = 15000 + 3600 = 18600 rupees.
500030053001300300560023003003005900330030030030062004

In the figure: The principal is 5000 rupees and the interest is 300 rupees every year. After year 1 the amount is 5300, after year 2 it is 5600, after year 3 it is 5900 and after year 4 it is 6200 rupees. Every year the amount grows by 300.

Rule 2: In simple interest the same interest comes every year, so the amount grows in equal steps — Amount = principal + (interest for 1 year × years).

  • Easy: Principal 5000 and interest 300 every year. Interest for 3 years = 300 × 3 = 900 rupees.
  • Medium: Principal 2000 and interest 160 every year. Amount after 2 years = 2000 + 160 × 2 = 2320 rupees.
  • Exam type: Principal 10000 and interest 700 every year. Amount after 5 years = 10000 + 700 × 5 = 13500 rupees.

Rule 3: Amount = principal × (100 + rate × years) ÷ 100 — This is a shortcut; the interest need not be found separately. The answer is the same as principal + interest.

  • Easy: Principal 100, rate 5, 3 years. 100 + 5 × 3 = 115. The amount is 115 rupees.
  • Medium: Principal 2000, rate 8, 1 year. 100 + 8 × 1 = 108. Amount = 2000 × 108 ÷ 100 = 2160 rupees.
  • Exam type: Principal 12000, rate 6, 3 years. 100 + 6 × 3 = 118. Amount = 12000 × 118 ÷ 100 = 14160 rupees.
Live figure

Total amount

In the app you can move this figure with your finger.

Open in the app
Remember

Amount = principal + interest. In the figure, 6000 + 900 = 6900.

Common mistake

Giving only the interest when the amount is asked. The interest is 900, but the amount is 6900.

Shortcut

Amount = principal × (100 + rate × years) ÷ 100. The two earlier ways and this way give the same answer; use it to check.

Spot the difference

PointInterestAmount
What it isThe extra moneyThe principal and the extra money together
Value in the figure9006900
How it is found from the otherAmount − principalPrincipal + interest
Compared with the principalUsually smallerAlways bigger

Practice questions

Easy
  1. 1The principal is 3000 rupees and the interest is 450 rupees. What is the amount?
  2. 2The principal is 2000 rupees and the interest for 1 year is 100 rupees. What is the amount after 1 year?
  3. 3The principal is 6000 rupees and the amount is 7000 rupees. What is the interest?
Medium
  1. 4Principal 6000 rupees, rate 3, 4 years. What is the amount?
  2. 5Principal 9000 rupees, rate 7, 2 years. What is the amount?
  3. 6Principal 5000 rupees and interest 150 rupees every year. What is the amount after 7 years?
Challenging
  1. 7Using the shortcut, find the amount: principal 20000 rupees, rate 5, 4 years.
  2. 840000 rupees are kept at rate 9 for 2 years. What amount will be received at the end?
Show answers (try them yourself first)
  1. 13000 + 450 = 3450 rupees.
  2. 22000 + 100 = 2100 rupees. 3) 7000 − 6000 = 1000 rupees.
  3. 4Interest = 6000 × 3 × 4 ÷ 100 = 720. Amount = 6000 + 720 = 6720 rupees.
  4. 5Interest = 9000 × 7 × 2 ÷ 100 = 1260. Amount = 9000 + 1260 = 10260 rupees.
  5. 65000 + 150 × 7 = 5000 + 1050 = 6050 rupees.
  6. 7100 + 5 × 4 = 120. Amount = 20000 × 120 ÷ 100 = 24000 rupees.
  7. 8Interest = 40000 × 9 × 2 ÷ 100 = 7200. Amount = 40000 + 7200 = 47200 rupees.

Finding the rate, principal and years

From daily life

An uncle said, "I put in some money and got 720 rupees of interest in 3 years." We can now work backwards and find what the rate was.

Simple definition

Among the principal, rate, years and interest, if any three values are known, the fourth can be found. On the interest side we multiply by 100, and on the other side we multiply the remaining numbers and divide.

Principal 6000 Years 3 Interest 720720 × 100 = 720006000 × 3 = 1800072000 ÷ 18000 = 4Rate = 4

In the figure: Principal 6000, years 3, interest 720. 720 × 100 = 72000. 6000 × 3 = 18000. Rate = 72000 ÷ 18000 = 4.

Rule 1: Rate = interest × 100 ÷ (principal × years) — First multiply the interest by 100, then divide by the product principal × years.

  • Easy: Principal 2000, 2 years, interest 200. 200 × 100 = 20000. 2000 × 2 = 4000. Rate = 20000 ÷ 4000 = 5.
  • Medium: Principal 5000, 4 years, interest 1400. 1400 × 100 = 140000. 5000 × 4 = 20000. Rate = 140000 ÷ 20000 = 7.
  • Exam type: Principal 8000 rupees and the amount after 3 years is 9440 rupees. Interest = 9440 − 8000 = 1440. 1440 × 100 = 144000. 8000 × 3 = 24000. Rate = 144000 ÷ 24000 = 6.
Amount 5400 Rate 7 Years 5100 + 7 × 5 = 1355400 × 100 = 540000540000 ÷ 135 = 4000Principal = 4000

In the figure: Amount 5400, rate 7, years 5. 100 + 7 × 5 = 135. 5400 × 100 = 540000. Principal = 540000 ÷ 135 = 4000 rupees.

Rule 2: Principal = amount × 100 ÷ (100 + rate × years), or principal = interest × 100 ÷ (rate × years) — If the amount is known use the first formula; if the interest is known use the second.

  • Easy: Interest 1260, rate 7, 3 years. 1260 × 100 = 126000. 7 × 3 = 21. Principal = 126000 ÷ 21 = 6000 rupees.
  • Medium: Amount 2700, rate 4, 2 years. 100 + 4 × 2 = 108. 2700 × 100 = 270000. Principal = 270000 ÷ 108 = 2500 rupees.
  • Exam type: Amount 14000, rate 8, 5 years. 100 + 8 × 5 = 140. 14000 × 100 = 1400000. Principal = 1400000 ÷ 140 = 10000 rupees.
Principal 3000 Rate 6 Interest 540540 × 100 = 540003000 × 6 = 1800054000 ÷ 18000 = 3Years = 3

In the figure: Principal 3000, rate 6, interest 540. 540 × 100 = 54000. 3000 × 6 = 18000. Years = 54000 ÷ 18000 = 3.

Rule 3: Years = interest × 100 ÷ (principal × rate) — First multiply the interest by 100, then divide by the product principal × rate.

  • Easy: Principal 1000, rate 5, interest 150. 150 × 100 = 15000. 1000 × 5 = 5000. Years = 15000 ÷ 5000 = 3.
  • Medium: Principal 4000, rate 8, interest 1280. 1280 × 100 = 128000. 4000 × 8 = 32000. Years = 128000 ÷ 32000 = 4.
  • Exam type: Principal 8000 rupees, amount 9600 rupees, rate 4. Interest = 9600 − 8000 = 1600. 1600 × 100 = 160000. 8000 × 4 = 32000. Years = 160000 ÷ 32000 = 5.
Live figure

Finding the rate, principal and years

In the app you can move this figure with your finger.

Open in the app
Live figure

Finding the rate, principal and years

In the app you can move this figure with your finger.

Open in the app
Live figure

Finding the rate, principal and years

In the app you can move this figure with your finger.

Open in the app
Remember

To find the rate, principal or years, start with interest × 100. In the figure, 720 × 100 = 72000 and 72000 ÷ 18000 = 4.

Common mistake

Treating the amount as the interest when the amount is given. First find interest = amount − principal, or for the principal use the divisor 100 + rate × years.

Shortcut

Check by putting the answer back. In the figure 6000 × 4 × 3 ÷ 100 = 720, so the rate 4 is right.

Spot the difference

PointFinding the rateFinding the years
Values knownPrincipal, years, interestPrincipal, rate, interest
Top numberInterest × 100Interest × 100
Bottom numberPrincipal × yearsPrincipal × rate
Division in the figure72000 ÷ 18000 = 454000 ÷ 18000 = 3

Practice questions

Easy
  1. 1Principal 4000 rupees, interest for 2 years 480 rupees. What is the rate?
  2. 2Principal 2000 rupees, rate 5, interest 300 rupees. How many years?
  3. 3Principal 3000 rupees, interest for 2 years 240 rupees. What is the rate?
Medium
  1. 4Amount 5600 rupees, rate 6, 2 years. What is the principal?
  2. 5Principal 6000 rupees, amount after 4 years 7200 rupees. What is the rate?
  3. 6The interest for 5 years is 1600 rupees and the rate is 8. What is the principal?
Challenging
  1. 7Principal 12000 rupees, amount 15600 rupees, rate 5. How many years?
  2. 8Amount 8800 rupees, rate 5, 2 years. What is the principal?
Show answers (try them yourself first)
  1. 1480 × 100 = 48000. 4000 × 2 = 8000. Rate = 48000 ÷ 8000 = 6.
  2. 2300 × 100 = 30000. 2000 × 5 = 10000. Years = 30000 ÷ 10000 = 3. 3) 240 × 100 = 24000. 3000 × 2 = 6000. Rate = 24000 ÷ 6000 = 4.
  3. 4100 + 6 × 2 = 112. 5600 × 100 = 560000. Principal = 560000 ÷ 112 = 5000 rupees.
  4. 5Interest = 7200 − 6000 = 1200. 1200 × 100 = 120000. 6000 × 4 = 24000. Rate = 120000 ÷ 24000 = 5.
  5. 61600 × 100 = 160000. 8 × 5 = 40. Principal = 160000 ÷ 40 = 4000 rupees.
  6. 7Interest = 15600 − 12000 = 3600. 3600 × 100 = 360000. 12000 × 5 = 60000. Years = 360000 ÷ 60000 = 6.
  7. 8100 + 5 × 2 = 110. 8800 × 100 = 880000. Principal = 880000 ÷ 110 = 8000 rupees.