Question

A certain sum is invested for certain time. it amounts to rs. 35 at 10% per annum. but when invested at 8% per annum, it amounts to rs. 30. find the time?

Answer 1

let the sum be p
si1=a1-p
=35-p
t=(35-p)×100/10×p
=350-10p/p
t=(30-p)×100/8×p
=375-12.5p/p
as both t are equal
375-12.5p/p=350-10p/p
= 375-12.5p=350-10p
=375-350=(12.5-10)p
=25=2.5p
=p=25/2.5
=10
t=20×100/8×10
=25years