In a certain year, a school had 60% boys and 40% girls as students. In the next five years the number of boys decreased by 10% and the number of girls increased by 10%. What is the change in total roll strength of the school in the five years ?
3% increase
2% decrease
No change
5% decrease
Answer is Right!
Answer is Wrong!
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UPSC CISF-AC-EXE – 2017
Initial Boys = 60% of 100 = 60 units.
Initial Girls = 40% of 100 = 40 units.
In the next five years:
Number of boys decreased by 10%. New number of boys = 60 * (1 – 0.10) = 60 * 0.90 = 54 units.
Number of girls increased by 10%. New number of girls = 40 * (1 + 0.10) = 40 * 1.10 = 44 units.
New total roll strength = New Boys + New Girls = 54 + 44 = 98 units.
The change in total roll strength = New Total – Initial Total = 98 – 100 = -2 units.
The percentage change = (Change / Initial Total) * 100 = (-2 / 100) * 100 = -2%.
A -2% change represents a 2% decrease.