Question

A sum of money when invested at simple interest amount to 4 times of itself after 12 years , it will become 10 times of itself after how many years??

Answer 1

Step-by-step explanation:

first case

let principal= X

then amount=4x

then simple interest=3x. (amount=principal+simple interest)

s.i.=p×r×t/100

3x=x×r×12/100

r=25%

second case

now

amount =10x

principal=X

rate=25%

time=??!

s.i.=9x

s.i.=p×r×t/100

9x=x×25×t/100

t=9/4

T=two years ten months