The percent of boys in a class was 40%. How many students are there in the class?

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Answer 1 · 2017-09-20T01:50:32

To answer the question it necessary to know either the number of boys or the number of girls in the class.

Answer 2 · 2017-09-20T07:50:27

A multiple of $5$ $5$

Percent means "per hundred", expressing a proportion.

The proportion of boys in the class is:

$40/100 = (2*color(red)(cancel(color(black)(20))))/(5*color(red)(cancel(color(black)(20)))) = 2/5$

In other words, for every $5$ students in the class, $2$ are boys and $3$ are girls.

In order that the figure $40%$ be exact, the number of students must be a multiple of $5$ .

Then the number of boys will be the corresponding multiple of $2$ and the number of girls the corresponding multiple of $3$ .

That is about as much as we can deduce from the question as given.