Answer
5 large boxes and 20 small boxes
Work Step by Step
We call x the number of large boxes and y the number of small boxes. Thus, we obtain:
$ x + y = 25 $
And
$ 3x +7.5y = 97.5$
In order to solve this problem, we multiply one or both of the equations by a value that will make one of the variables cancel. We multiply the top equation by -3, and we multiply the bottom equation by 1. Then, we add the two equations to obtain:
$4.5y = 22.5 \\ y =5 $
We plug in the given value into the top equation and solve for the other variable:
$ x + 5 = 25 \\ x =20$
