Percentage - Aptitude MCQ Questions and Solutions with Explanations

Answer: Option B

Percentage annual increase :
$$\eqalign{ & = \left( {\frac{{75}}{{1000}} \times 100} \right)\% \cr & = 7\frac{1}{2}\% \cr & = \frac{{15}}{2}\% \cr} $$
Population after 2 years :
$$\eqalign{ & = 4200000{\left( {1 + \frac{{15}}{{2 \times 100}}} \right)^2} \cr & = \left( {4200000 \times \frac{{43}}{{40}} \times \frac{{43}}{{40}}} \right) \cr & = 4853625 \cr} $$

Answer: Option D

Let B + M + D = $$x$$
Then,
B = 25 of $$x$$ - 20
$$\eqalign{ & = \left( {\frac{{25x}}{{100}} - 20} \right) \cr & = \left( {\frac{x}{4} - 20} \right) \cr} $$
And D = 50
∴ $$\frac{x}{4}$$ - 20 + M + 50 = $$x$$
or M = $$\left( {\frac{{3x}}{{4}} - 30} \right)$$
So, marks in Maths cannot be determined.

Answer: Option C

x = 63% of y
⇒ x = $$\frac{63y}{100}$$
⇒ y = $$\frac{100x}{63}$$
∴ Required percentage :
$$\eqalign{ & = \left( {\frac{{{y^2}}}{{{x^2}}} \times 100} \right)\% \cr & = \left[ {{{\left( {\frac{{100x}}{{63}}} \right)}^2} \times \frac{1}{{{x^2}}} \times 100} \right]\% \cr & = \left( {\frac{{10000}}{{3969}} \times 100} \right)\% \cr & = 251.96\% \approx 250\% \cr} $$