Page 126 - ICSE Math 7

2. Find the principal that will amount to ` 8,480 in 3 years at the rate of 2% p.a.
3. Rahul borrowed a sum of money from a money lender for which he had to pay interest at the
rate of 15% p.a. He paid ` 10,400 at the end of two years to clear the loan along with interest.
Find the sum he borrowed.
4. The interest on ` 500 amounts to ` 60 in 2 years at the same rate of interest per annum. In how
much time will ` 800 amount to ` 1,232 with the same rate?
5. Sia took a loan from a money lender at 20% per annum. After some time, she paid back the loan
by paying ` 89,600. If the total interest was ` 33,600, find the time period.
6. Two friends invested ` 7,000 and ` 15,000 at the same rate of interest p.a. If at the end of 5 years,
one friend received ` 600 more than the other, find the rate of interest.
7. In how much time will the interest on a sum of money will be half the money at 5% p.a.?
8. Aman earns ` 1,470 as interest after 3 years at 7% per annum. How much did he invest?

AT A GLANCE

P × R × T
¾ Simple Interest (S.I.) = 100 , where P = Principal, R = Rate of interest and T = Time
S.I. × 100
¾ Principal (P) =
R × T
S.I. × 100
¾ Rate of interest (R) = P × T
S.I. × 100
¾ Time (T) =
P × R
¾ Amount (A) = Principal + Simple interest = P + S.I.

MENTAL MATHS

1. Complete the table given below.

Principal (in `) Simple interest (in `) Amount (in `)
900 90 _____
1,000 _____ 1,250

2,400 2,400 _____
_____ 150 800
3,590 _____ 3,680

2. Fill in the blanks.

(a) Money borrowed is known as __________________.
(b) Extra money paid is known as __________________ and the total money paid is known as
__________________.
(c) If rate of interest is given in months, then time period is in __________________.

(d) If a certain sum of money doubles itself in 5 years, then the rate of simple interest is
__________________.

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