Question

A certain sum becomes rs.1020 in 5 years and rs.1200 in 8 years at si. Find principal

Answer 1

Interest for 3 years = Amount after 8 years - Amount after 5 years = 1200 - 1020 = 180

So, interest for 1 year = 180/3 = 60

Interest for 5 years = 5*60 = 300

Principal = Amount after 5 years - Interest for 5 years = 1020 - 300 = 720