A sum becomes its double in 10 years. Find the annual rate of simple interest.
(a)8\%
(b)5\%
(c)10\%
(d)20\%
Answer
Answer (as printed): C
Explanation
Let sum be ₹$x$ and let S.I. = ₹$x$. Time = 10 years. ∴ Rate $=\frac{\text{S.I.} \times 100}{\text{Principal} \times \text{Time}}=\frac{x \times 100}{x \times 10}=10\%$ per annum.
Explanation as extracted from the printed page; notation may be imperfect.