Question

At what rate percent of simple interest will the interest on Rs.3750 be one-fifth of itself in 4 years? To what will it amount in 15 years?

Answer 1

P = Rs.3750

I = Rs.`3750xx1/5` = Rs.750

T = 4 years

R =`(100xx"I")/("P"xx"T")`

`=(100xx750)/(3750xx4)`

= 5%

Again, P = Rs.3750

The interest of 4 years = Rs.750

The interest of 1 year = Rs.`750/4`

Interest of 15 years = Rs.`750/4xx15`

= Rs.`(750xx15)/4`

= Rs.`5625/2`

= Rs.2812.50

Amount in 15 years will be = Rs.3750 + Rs.2812.50

= Rs.6562.50

∴ Rate = 5%

The amount in 15 years will be = Rs.6562.50