Answer:
After 3 hours Amanda catch up to Ben.
Explanation:
Speed of Ben = 4 mi/h
Speed of Amanda = 6 mi/h
Time after Amanda starts after Ben leaves = 1.5 hours.
Let the time taken for them to catch up be t hours.
Distance traveled by Ben in time (t+1.5) = 4*(t+1.5)
Distance traveled by Amanda in time t = 6*t
Equating both the distances
4*(t+1.5)= 6*t
2t = 6
t = 3 hours
So after 3 hours Amanda catch up to Ben.