Question

Simple interest on a certain  sum of money for 3 years  at 18% per annum is half the compound interest on Rs. 9000 for 2 years  at 10% per annum. The sum placed on simple  interest is:

Options:

1) Rs 3500

2) Rs 875

3) Rs 1750

4) Rs 1400

Answer 1

so the answer is option C. I hope this will clear your doubts related to this question .

Answer 2

Answer:

Option 3 - The required sum placed on simple interest is Rs.1750.                  

Step-by-step explanation:

Given : Simple interest on a certain  sum of money for 3 years  at 18% per annum is half the compound interest on Rs. 9000 for 2 years  at 10% per annum.

To find : The sum placed on simple interest is ?

Solution :

The compound interest formula is $CI=A-P$

Where, $A=P(1+r)^t$

A is the amount

P is the principal P=9000

r is the interest rate r=10%=0.1

t is the time t=2 years

Substitute the value in the formula,

$A=P(1+r)^t$

$A=9000(1+0.1)^2$

$A=9000(1.1)^2$

$A=9000(1.21)$

$A=10890$

Compound interest is

$CI=10890-9000$

$CI=1890$

Simple interest on a certain sum of money for 3 years  at 18% per annum is half the compound interest.

i.e. Simple interest = $\frac{1890}{2}=945$

R=18%=0.18

T=3 years

Using simple interest formula,

$S.I=Sum\times R\times t$

$Sum=\frac{S.I}{R\times T}$

$Sum=\frac{945}{0.18\times 3}$

$Sum=\frac{945}{0.54}$

$Sum=1750$

Therefore, The required sum placed on simple interest is Rs.1750.

So, Option 3 is correct.