A sports club has 40 members, with boys and girls in the ratio 3 : 1. How many girls must join, with…
The starting ratio gives 30 boys and 10 girls. Keeping 30 boys, a ratio of 3 : 2 requires 20 girls. The club must add 10 girls.
Choose your answer
A sports club has 40 members, with boys and girls in the ratio 3 : 1. How many girls must join, with the number of boys unchanged, to make the ratio 3 : 2?
Answer and explanation
Correct answer C
The starting ratio gives 30 boys and 10 girls. Keeping 30 boys, a ratio of 3 : 2 requires 20 girls. The club must add 10 girls.
Option feedback
Option A
Adding 11 girls gives 30 boys and 21 girls. The target is 30 boys and 20 girls.
Option B
Adding 9 girls gives 30 boys and 19 girls. The target is 30 boys and 20 girls.
Option C
There are 30 boys and 10 girls initially. The target ratio requires 20 girls, so 10 must join.
Option D
Adding 5 girls gives 30 boys and 15 girls, a ratio of 2 : 1.
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West Bengal Judicial Services