Ben starts walking along a path at 4 mi/h. one and a half hours after ben leaves, his sister amanda begins jogging along the same path at 6 mi/h. how long will it be before amanda catches up to ben?

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.

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