Question

If the simple interest on a certain sum of money is $\frac{1}{100}$th of the sum and the rate per cent equals to 9 times the number of years, then the rate of interest per annum is

• A. $1$%
• B. $2$%
• C. $3$%
• D. $4$%

Answer 1

Answer: (C)

$3$%

$SI=P/100;r=9t⟹t=r/9$

$SI=\frac{P\times r\times t}{100}$

$⟹\left(P/100\right)=\frac{P\times r\times \left(r/9\right)}{100}$

$⟹r\times \left(r/9\right)=1⟹r=3\%$