Answer:
60mph
Step-by-step explanation:
Let d be the distance. Let v be the speed of car a. That means the speed of car b is v + 15. Now we can set up 2 equations using the v = d/t:
Car a: v = d / 2 --> d = 2v
Car b: v + 15 = d / 1.5
We can solve for v by substituting the first equation (rearranged to isolate d) into the second:
v + 15 = 2v / 1.5
1.5v + 22.5 = 2v
0.5v = 22.5
v = 45
We're looking for the speed of car b, which was v + 15 = 45 + 15 = 60.
