Question

Find the rate at which rs 4000 will give rs630.50 as compound interest in 9 months,interest being compounded quarterly?

Answer 1

Correct Answer:

A) 20%


Description for Correct answer

Given, P = RS. 4000, n = 9 months = 3/4yr

and CI= RS. 630. 

Amount = P + CI = 4000 + 630.50 = rs. 4630.50 

According to the formula, 

Amount = P(1+R100×4)4n


4000(1+R400)4×3/4 = 4630.50

=4000(400+R400)3
=4630.50

4630.504000

(400+R400)3


=>

9261

8000

92618000

=(400+R400)3

=> (2120)3

(400+R400)3

=> 400+R= 21×20 =420

400+R = 420

R=420-400=20%