SOLUTION: Ben starts walking along a path at 2 mi/h. One and a half hours after Ben leaves, his sister Amanda begins jogging along the same path at 4 mi/h. How long will it be before Amanda

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: Ben starts walking along a path at 2 mi/h. One and a half hours after Ben leaves, his sister Amanda begins jogging along the same path at 4 mi/h. How long will it be before Amanda       Log On


   

Question 1065407: Ben starts walking along a path at 2 mi/h. One and a half hours after Ben leaves, his sister Amanda begins jogging along the same path at 4 mi/h. How long will it be before Amanda catches up to Ben ?
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
                SPEED      TIME       DISTANCE
BEN              2         t+1.5        d
AMANDA           4          t           d


RT=D, constant travel rates rule for rate R, time T, distance D.

system%282%28t%2B1.5%29=d%2C4t=d%29

Distance for each is the same d.

2%28t%2B1.5%29=4t
t%2B1.5=2t
t=1.5------------- One and a half hours for Amanda to catch-up to Ben.

Answer by ikleyn(52787) About Me  (Show Source):
You can put this solution on YOUR website!
.
Ben starts walking along a path at 2 mi/h. One and a half hours after Ben leaves, his sister Amanda begins jogging along
the same path at 4 mi/h. How long will it be before Amanda catches up to Ben ?
~~~~~~~~~~~~~~~~~~~~~~~~ 

When Amanda started jogging, Ben just was 1.5 hours * 2 mi/h = 3 miles ahead.


Starting from this moment, the distance between them decreases in (4 mi/h - 2 mi/h) = 2 mi/h every hour.


Hence, Amanda will catch up to Ben in 3%2F2 = 1.5 hours.

You can solve this problem by any of these two methods.

They both are correct.