Answer:
Bulawayo
Explanation:
Proportions can be compared numerous ways. Here, we find it convenient to look at the difference between girls and boys relative to the number of boys.
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Harare
With 35 girls and 25 boys, there are 10 more girls than boys. 10 is less than half of the number of boys, so the ratio of girls to boys is less than 1.5.
Bulawayo
With 35 girls and 15 boys, there are 8 more girls than boys. 8 is more than half of the number of boys, so the ratio of girls to boys is more than 1.5.
Comparision
"More than 1.5" is greater than "less than 1.5", so Bulawayo has the greatest proportion of girls.
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Additional comment
As a fraction of the total, the proportions of girls are ...
Harare: 35/(35+25) = 35/60 = 7/12 = 21/36
Bulawayo: 22/(22+14) = 22/36 . . . . . . greater than 21/36.