Question

a sum of money trebles itself in 20 years at simple interest . find the rate of the interest

Answer 1

let sum be x
amount = 3x
si = 3x -x = 2x
rate= 2x×100/x×20
10%

Answer 2

Concept

The method of computing interest on a given principle amount of money is known as simple interest (S.I.)

Given

Given that a sum of money trebles itself in 20 years at simple interest

Find

We need to find  the rate of the interest.

Solution

Let principal be x , rate of interest be I and time = 20 years

Amount = 3x as it trebles

So the interest = 3x-x = 2x

Now the percentage rate of 20 years

( I = PRN /100)

2 = 20/100*R

Therefore

2*100 / 20 = R

100/10 = R

Therefore R = 10

Hence the rate of interest is 10%

#SPJ2