The ratio of the number of ladies to that of gents at a party was 3 : 2. When 20 more gents joined the party… · ABC26GN3127
Subject: General Aptitude · Chapter: Ratio and Proportion · Exam: C.P.O. 2006
The ratio of the number of ladies to that of gents at a party was 3 : 2. When 20 more gents joined the party, the ratio was reversed. The number of ladies present at the party was
(a)16
(b)24
(c)32
(d)36
Answer
Answer (as printed): B
Explanation
Let the number of ladies and gents at the party be $3 x$ and $2 x$ respectively. Then, $$\frac{3 x}{2 x+20}=\frac{2}{3} \Rightarrow 9 x=4 x+40 \Rightarrow 5 x=40 \Rightarrow x=8 .$$ ∴ Number of ladies $=3 \times 8=24$.
Explanation as extracted from the printed page; notation may be imperfect.