Anybody any good at maths?

[Globalti]

Help me with this: last night Ben and Alex went down to the park where they met John and Mary. They knocked John and Mary over and stole their bikes, riding off laughing to each other and exclaiming "wasn't that fun!"

They rode the bikes up some really big hills, nearly a thousand feet of climbing. It was 9.4 miles to the top and when they got there Ben saw that they had averaged 12.4 miles an hour. Going back was nearly all downhill and when they got back to the park they had ridden 23.2 miles in 1 hour and 28 minutes at an overall average of 15.6 mph. They still agreed they had had fun but their legs felt tired.

What was Ben and Alex's average speed from the top of the hill back to the park?

 

[hoopdriver]

How come it was longer on the way back?

 

[buddha]

Ascent time = 9.4 miles /12.4 mph = 0.758 hours
Descent time = (1 + 28/60) - 0.758 = 0.709 hours
Descent distance = 23.2 - 9.4 = 13.8 miles
Descent speed = 13.8 / 0.709 = 19.5 mph

 

[redcard]

How come it was longer on the way back?

All signs suggest a computer malfunction.

 

[compo]

How come it was longer on the way back?

The road was an anti-clockwise circular route up the climb, so coming down in a clockwise direction would put the riders on the outside lane , hence further to cycle.

 

[Globalti]

D'oh! What a silly question! They didn't come back the same way they went out!

Anyway Buddha gets the prize, step up and receive your gold star!

 

[Night Train]

Who cares what their speed was?
And where are the Police when you need them?

Ben and Alex should be strung up in the park as a warning to others! Bleeding bike thieves!

Did John and Mary get their bikes back?

I take it that was not a true story.

 

[Globalti]

Some of it was true!