Question

on what sum will the compound interest at 7 1\2 % p.a for 3yrs compounded annually be Rs 3101.40 ?​

Answer 1

Given:

R= 15/2% , n= 3 years

Let the principal be ₹100

Amount (A) = P(1+R/100)^n

A= 100 (1+15/200)^3

A= 100( 1+3/40)^n

A= 100( 43/40)³

A= 100 (79507/64000)

A= 79507/640

A=₹ 124.23

Compound Interest (C.I)= A-P

C.I= 124.23 - 100= ₹24.23

If compound interest is ₹24.23, principal = ₹100

If compound interest is ₹1 , principal= 100/24.23

If compound interest is ₹ 3101.40 ,principal= (100/24.23)× 3101.40

= 310140/24.23= 12799.83

Hence, the sum is= ₹ 12799.83

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Hope this will help you...