Let
x ----->number of multiple-choice questions
y ----> number of word problems
so
we have
x+y=35 --------> equation 1
2x+7y=100 -----> equation 2
solve the system of equations
Solve by graphing
using a graphing tool
see the attached figure
therefore
x=29
y=6
number of multiple-choice questions is 29
number of word problems is 6