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

Please help with a good and clear explanation!

2 Answers
Sep 20, 2017

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

Sep 20, 2017

A multiple of #5#

Explanation:

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.