Answer:
a
Step-by-step explanation:
because thats the point of intersection meaning for 4 hours it costs 70$ for both
the slope for company a is y = 10x + 30
the slope for company b is y = 5x + 50
and if you plug in 4 for x in both
10(4) + 30 = 40 +30 = 70
5(4) + 50 = 20 + 50 = 70
