A Sum Becomes its Double in 10 Years. Find the Annual Rate of simple Interest.
Answer: (3) 10 %
Let the principal is Rs.X and rate = R
Then, Amount = 2 X
Simple interest = 2 X – X = X
Simple Interest = P x R x T/100
Where, P = principal , R = rate, & T = time.
X = X x R x 10/100
1 = R / 10
R = 10 % .
Then, the rate is 10 %.
Hence, the answer is (3) 10 %.