Question

If a sum of money at simple interest doubles in 12years, the rate of interest per annum is?

• A. $$16\frac{2}{3}$$$$
• B. 7.5%
• C. $8\frac{1}{3}$$$%
• D. 10%

Answer 1

Answer:

C. $8\frac{1}{3}$$$%

$$Let the sum be X</p><p style="color: rgb(0,0,0); margin-top: 2px; margin-bottom: 2px" data-pxy="true">$$Sum after 12years be 2X

$Interest Rate per Annum=\frac{(Total Amount-Principal}{Principal\times{Number of years}}\times100$

$=\frac{2X-X}{12X}\times100$

$=\frac{X}{12X}\times100$

$=8\frac{1}{3}$$$%