Question

A certain sum become 3 times at the rate of 8% per annum. At what rate of interest thesame sum become 6 times in same duration​

Answer 1

Given:

A certain sum becomes 3 times at the rate of 8% per annum

To find:

At what rate of interest the same sum become 6 times in the same duration​

Solution:

Let the principal is ₹P

Here we have given that sum becomes 3 times at the rate of 8% per annum

So we get the interest as 2P only

So by the Concept of the Simple interest, we get:

SI = PRT/100

2P = P×8×T/100

2 = 8×T/100

T = 100/4

T = 25 years

Now the amount is 6 times in the same time period.

So the simple interest will be 5P

SI = PRT/100

5P = P×R×25/100

5 = R×25/100

R = 100/5

R = 20%

So the rate of the interest should be 20%