Interest - Aptitude MCQ Questions and Solutions with Explanations

Answer: Option B

$$\eqalign{ & {\text{We}}\,{\text{can}}\,{\text{use}}\,{\text{formula}}\,{\text{of}}\,{\text{compound}}\,{\text{interest}} \cr & A = P \times {\left[ {1 + \left( {\frac{r}{{100}}} \right)} \right]^n} \cr & A = 2100 \times {\left[ {1 + \left( {\frac{5}{{100}}} \right)} \right]^2} \cr & A = 2100 \times {\left[ {\frac{{105}}{{100}}} \right]^2} \cr & A = \frac{{ {2100 \times 11025} }}{{10000}} \cr & {\text{Hence,}}\,{\text{Amount}}\,A = Rs.\,2315.25 \cr} $$

Answer: Option A

$$\eqalign{ & {\text{The}}\,{\text{difference}}\,{\text{between}}\,{\text{compound}}\,{\text{interest}}\,{\text{and}} \cr & {\text{simple}}\,{\text{interest}}\,{\text{over}}\,{\text{two}}\,{\text{years}}\,{\text{is}}\,{\text{given}}\,{\text{by}} \cr & \frac{{{{\Pr }^2}}}{{{{100}^2}}}\,or\,P{\left( {\frac{r}{{100}}} \right)^2} \cr & {\text{Here,}}\,{\text{Principal}}\,\left( P \right) = Rs.\,2000 \cr & {\text{Rate}}\,\left( r \right) = 5\% \cr & {\text{Now}}\,{\text{difference}}, \cr & D = \frac{{ {2000 \times 5 \times 5} }}{{ {100 \times 100} }} \cr & D = Rs.\,5 \cr} $$