Subject: General Aptitude · Chapter: Ratio and Proportion · Exam: · Marks: · Difficulty:
The weights of two persons $A$ and $B$ are in the ratio of $3 : 5$. $A$'s weight increases by 20\% and the total weight of $A$ and $B$ together becomes 80 kg, with an increase of 25\%. By what percent did the weight of $B$ increase?
(a)20\%
(b)25\%
(c)28\%
(d)30\%
Answer
Answer (as printed): C
Explanation
Let the initial total weight of $A$ and $B$ be $x$ kg. Then, $125\%$ of $x=80 \Rightarrow x=80 \times \frac{100}{125}=64$ kg. $A$'s initial weight $=\left(\frac{3}{8} \times 64\right)$ kg $=24$ kg. $B$'s initial weight $=\left(\frac{5}{8} \times 64\right)$ kg $=40$ kg. $A$'s new weight $=120\%$ of $24$ kg $=28.8$ kg. $B$'s new weight $=(80-28.8)$ kg $=51.2$ kg. Increase in $B$'s weight $=(51.2-40)$ kg $=11.2$ kg. $\therefore$ Increase $\%=\left(\frac{11.2}{40} \times 100\right)\%=28\%$.
Explanation as extracted from the printed page; notation may be imperfect.