Answer: 10 buses
Explanation:
This problem can be used using a system of two equations since there are two variables:
v + b = 15
10v + 25b = 300
solve for b and substitute into the second equation:
b = 15 - v
10v + 25 (15 - v) = 300
10v + 375 -25v = 300
-15v = -75
v = 5
b = 15 - v = 15 - 5 = 10