Roland2rule wrote:Andy starts his journey from A to B and Ben starts his journey from B to A at the same time.After passing each other they complete their journeys in 3 1/3 and 4 4/5 hours respectively.Find the speed of Ben if Andy traveled at 12 miles/hr.
a) 8.33 m/hr
b) 10 m/hr
c) 22 m/hr
d) 20 m/hr
e)16.66 m/h
OA is B
Is there a specific formula to solve this question? An expert should comment pls.Thanks a lot.
The situation is depicted in the diagram below.
For Andy:
A <----------------Say x miles @ 12 mph------------------>
M <------12 mph x 3 1/3 hrs = 40 miles-------->
B
A and B are starting points and M is their meeting point
For Ben:
A <----------------Say x miles / 4 4/5 hrs = 5x/24 mph------------------>
M <------40 miles-------->
B
Say Ben's speed is S, then S = Distance from A to M divided by time taken by Ben to reach A from point M. So, S = x miles / (24/5 hrs) = 5x/24 mph
Time taken by Andy to reach from Point A to point M = x / 12 hrs ---(1)
Time taken by Ben to reach from Point B to point M = 40 / (5x/24) hrs ---(2)
Since (1) and (2), we have x / 12 = 40 / (5x/24) => x = 48
Thus, the speed of Ben = 5x/24 mph = 5*48/24 = 10 mph
The correct answer:
B
Hope this helps!
-Jay
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