Correct Answer - Option 1 : 10%
Given:
Simple interest = 1/2(Principal)
Time (T) = 1/2(rate of interest)
Concept:
Simple interest is the interest calculated on the principal portion of the loan or the original contribution to the saving account.
Formula Used:
Simple Interest = (P × R × T)/100
Calculation:
Let the principal be '2P'
⇒ Simple interest = 1/2(2P) = P
Also, let the rate of interest be '2R'
So, time = (1/2)2R = R years
Simple Interest = (P × R × T)/100
⇒ P = (2P × 2R × R)/(100)
⇒ 100 = 4R2
⇒ R2 = 100 ÷ 4 = 25
⇒ R = 5
So, rate percent per annum = 2R = 10%
∴ The rate percent per annum is 10%.