Question
In a class, the ratio of number of boys to number of
girls is 6:5. If 1 boy joined the class and 5 girls left the class, then the ratio becomes 7:5. Find the actual number of girls in the class.Solution
Let initially the number of boys and girls be 6x and 5x, respectively.
(6x + 1) : (5x − 5) = 7 : 5
Or, 5(6x + 1) = 7(5x − 5)
Or, 30x + 5 = 35x − 35
Or, 5x = 40 ⇒ x = 8
Therefore, number of girls = 5 × 8 = 40Â
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