Subject: General Aptitude · Chapter: Ratio and Proportion · Exam: · Marks: · Difficulty:
How many students are there in the class? I. Boys and girls are in the ratio of 2 : 3 respectively. II. Difference between the number of girls and the number of boys is 8 and 60% of the students are girls.
Answer
SELF-PRACTICE — the source book printed no answer.
Nothing is invented here, so this question has no answer on record.
Explanation
I. Let the number of boys and girls be $2x$ and $3x$ respectively. II. Let the total strength of the class be $x$. Then, number of girls $=60\%$ of $x=\frac{3x}{5}$; number of boys $=40\%$ of $x=\frac{2x}{5}$. So, $\frac{3x}{5}-\frac{2x}{5}=8 \Rightarrow \frac{x}{5}=8 \Rightarrow x=40$. $\therefore$ Total number of students $=40$. Thus, II alone gives the answer while I alone does not. $\therefore$ Correct answer is (b).
Explanation as extracted from the printed page; notation may be imperfect.