the ratio of the number boys and girls in a school is..., Ratio & Proportion, General Mathematics

Question:The ratio of the number of boys and girls in a school is `3 : 2`. It `20%` of the boys and `25%` of the girls are scholarship holders, the percentage of the school students who are not scholarship holders is :

A `56` 
B `70` 
C `78` 
D `80`

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+ AnswerC

+ ExplanationLet boys `= 3x` & girls `= 2x`.

Number of those who are not scholarship holders

`= 80% of 3x + 75% of 2x`

`=((80)/(100) xx 3x + (75)/(100) xx 2x)`

`=(39x)/(10)`.

`=(78)/(100) xx (5x)`

`= 78%` of the total.

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