Question

the CI for a sum of money for 2 years at the rate of 10% per annum compounded annually is rupees 315 find the simple interest on the same sum for the same period at the same rate

Answer 1

315=p(1+10/100)^2
p=260.33
I=260.33×10×2/100
=52.066(approx)

Answer 2

Solution :-

Compound Interest for 2 years = Rs. 315

Let the Principal be Rs. P

Then, the Amount (Principal + Interest) = Rs. P + 315

Now, using formula of compounded interest.

A = P(1 + R/100)ⁿ

⇒ P + 315 = P(1 + 10/100)² 

⇒ P + 315 = P × 11/10 × 11/10

⇒ P + 315 = 121P/100

⇒ 100P + 31500 = 121P

⇒ 121P - 100P = 31500

⇒ 21P = 31500

⇒ P = 1500

So, the Principal is Rs. 1500

Now,

Simple Interest = (P × R × T)/100

⇒ S.I. = (1500 × 10 × 2)/100

⇒ S.I. = 30000/100

S.I. = Rs. 300 

So, Simple Interest for  2 years @ 10 % on Rs. 1500 is Rs. 300

Answer.