The distance between A and B is 3400 m. Amy walks from A to B in 40 minutes and takes 5 minutes more to return to A. What is Amy's average speed in m/min for the whole journey from A to B and back to A again?

The distance between A and B is 3400 m. Amy walks from A to B in 40 minutes and takes 5 minutes more to return to A. What is Amy's average speed in m/min for the whole journey from A to B and back to A again?

1 Answer
Dec 29, 2017

#80#m/min

Explanation:

Distance between A to B = #3400m#
Distance between B to A = #3400m#

Therefore, total distance from A to B and back to A = #3400+3400# = #6800m#

Time taken by Amy to cover the distance from A to B = #40 min#
and, time taken by Amy to return back from B to A = #45 min# (because she takes #5# more minutes in the return journey from B to A)

So, total time taken by Amy for the entire journey from A to B to A = #40+45 = 85min#

Average speed = total distance/total time = #(6800m)/(85min)# = #80# m/min