It takes Joey the postman 1 hours to run a 7 mile long route every day. He delivers packages and then returns to the post office along the same path. If the average speed of the round trip is 8 mile/hour, what is the speed with which Joey returns?
Choices.
A) 11
B) 12
C) 13
D) 8
E) 15
let his speed for one half of the journey be 7 miles an hour   let the other half be x miles an hour   now,   avg speed =8 mile an hour   2*7*x/7+x=8   14x=8x+56=&gt;x=8   8
<result>D</result>
It takes Joey the postman 1 hours to run a 7 mile long route every day. He delivers packages and then returns to the post office along the same path. If the average speed of the round trip is 8 mile/hour, what is the speed with which Joey returns?