Answer:
28
Step-by-step explanation:
If g is the number of green marbles, and b is the number of blue marbles, then:
g + b = 36
g = 4 + 3b
Solve the system of equations. Using substitution:
(4 + 3b) + b = 36
4 + 4b = 36
4b = 32
b = 8
Therefore:
g = 28
