From the following information in the problem, we construct the following equations: (assuming that we use m=movies and v=video games.)
1.7m+9v=78
2. 5m+3v=36
Using the method of substitution:
7m+5m+9v+3v=114
12m+12v=114
m+v=19/2
and so m=19/2-v.
Substituting this into equation 1, we get:
7(19/2-v)+9v=78
66.5+2v=78
2v=11.5
v=5.75 and so m=3.75