Question 1007322
.
M=number of multiple choice; W=word problems
.
M+W=25
M=25-W
.
3M+4W=90
3(25-W)+4W=90
75-3W+4W=90
W=15
ANSWER 1: There were 15 word problems.
.
M=25-W
M=25-15
M=10
ANSWER 2: There were 10 multiple choice problems.
.
CHECK:
3M+4W=90
3(10)+4(15)=90
30+60=90
90=90