Question
In a class, the ratio of number of boys to number of
girls is 5:3. If 2 boys joined the class and 3 girls left the class, then the ratio becomes 7:4. Find the actual number of girls in the class.Solution
Let initially the number of boys and girls be 5x and 3x, respectively.
(5x + 2) : (3x − 3) = 7 : 4
Or, 4(5x + 2) = 7(3x − 3)
Or, 20x + 8 = 21x − 21
Or, x = 29
Therefore, number of girls = 3 × 29 = 87Â
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