percentage of boys enrolled in school in september was 20% and in october it went up to 25%

Question

in September the enrollment number was 1200 and 20% of the students were boys.  in October the percentage of boys was 25%.  how many boys enrolled in the school in October?

Answer 1

Mindy,

 

In September there were 20% boys with total students being 1200

 

So number of boys = 20/100*1200 = 240

Here we have to assume that no girls joined in October

 

Let x be the number of boys who joined in October.

Total boys in October = 240 + x

Total students in October = 1200 + x

Boys are 25% of total students

 

so (25/100)*(1200+x) = 240 + x

300 + .25x = 240 + x

0.75 x = 60

x= 80

 

So 80 boys enrolled in October