Question

find the compound interest on Rs.1400 for 9 months at 12% per annum if the interest is compounded quarterly.

Answer 1

A = P ( 1 + R/4 )^4n and C.I. = A – P
Where, P = Principal
R = Rate of interest p.a (per annum i.e annually)
n = number of years.

Here, P = 1400, R = 12% p.a. and n = 3/4 year.
∴ Amount after 3/4 year = P ( 1 + R/4 )^4n
= 1400 x ( 1 + 12/4 )^4 x 3/4
= 1400 x ( 1 + 3)^3
= 1400 x (4 )^3
= 1400 x 64
= Rs. 89600
∴ Compound interest
= 89600– 1400 = Rs.88200