Question

9. If a sum of money doubles itself in 8 years at S.l. then the rate percent per annum is


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Answer 1

Let sum = x then Simple Interest = x

Rate = (100 * x) / (x * 8) = 12.5

Answer 2

Here the sum of money is the Amount=A

which means that in 8years the A was twice the principal = P.

therefore in 8 years rate of interest summed up to 100%

therefore for one year

the rate of interest=100÷8= 12.5

therefore the rate of interest per annum is 12.5%.