SSC MTS 2022 PYQ — Question 69

The correct answer is option 1 i.e. 12.5%

Let the principal amount be P and the rate of interest be R% - 

Case 1 -

Amount after 7 years = $P\left ( 1+\frac{7R}{100} \right )$

24000 = $P\left ( 1+\frac{7R}{100} \right )$

Case 2 - 

Amount after 12 years = $P\left ( 1+\frac{12R}{100} \right )$

32000 = $P\left ( 1+\frac{12R}{100} \right )$

On dividing 1 by 2 - 

$\frac{24000}{32000}= \left ( \frac{1+\frac{7R}{100}}{1+\frac{12R}{100}} \right )$

$\frac{24000}{32000}=\frac{100+7R}{100+12R}$

24000(100 + 12R) = 32000(100 + 7R)

2400000 + 288000R = 3200000 + 224000R

64000R = 3200000 - 2400000

R = 800000 ÷ 64000 

R = 12.5 

Thus, rate of simple interest paid per annum is 12.5%.