The simple interest on a sum of money is \(\frac{8}{25}\) of the sum. If the number of years is numerically half the rate percent per annum, then the rate percentt per annum is:
Answer & explanation
Correct answer: option 4
Say, Sum = 25
S.I. = 8
here, Time = \(\frac{1}{2}\) x rate
⇒ 8 = \(\frac{25 × R × R}{100 × 2}\)
⇒ 8 = \(\frac{R^2}{8}\)
⇒ Rate of interest = \(\sqrt {64}\) = 8%