Question

at what rate would sum of rs4000 yield rs1324 as compound interest in 3yrs?

Answer 1

P=Rs 4000
C.I.=Rs 1324
n=3yrs
A=P (1+r/100)^n
4000+1324=4000 (1+r/100)^3
5324/4000=(1+r/100)^3
(11/10)^3=(1+r/100)^3
1+r/100 = 11/10
r/100=11/10- 1
=1/10
r=10%
☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆
hope it's correct

Answer 2

Given,

Principal = p = Rs.4000

Compound Interest = CI = Rs.1324

Time = t = 3 years.

Rate of interest = ?

Let Rate of interest be = r %

We know,

Compound Interest=CI= P(1+r/100)^t - P

Then,

⇒4000(1+r/100)^3 = 5324       [4000+1324 = 5324]

⇒(1+r/100)^3 = 5324/4000

⇒(1+r/100)^3 = 1331/1000

⇒(1+r/100)^3 = 11^3/10^3

⇒(1+r/100)^3 = (11/10)^3

⇒r/100 = 11/10 - 1

⇒r/100 = 11-10/10

⇒r/100 = 1/10

⇒r=1/10 × 100

⇒r=10×1

⇒r=10

Hence, Rate of interest = 10%