Question

The principal, at a certain rate of interest, doubles in 5 years by the
simple interest. In how many years, the same principal with the same
rate of interest becomes five times?
(3) 20 years
(4) 25 years
(1) 10 years
the rate of 7 p.c.p.a. How much
(2) 12 years​

Answer 1

Answer:

It doubles in 5 years inetrest . It means we received rs. 100 as interest. So interest rate is 100/5=20%.

When the principal becomes 5 times it means interest earned is 400

Number of years required=400/20=20