It takes Joey the postman 1 hours to run a 5 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?
Choose the most appropriate option:
A) 11 B) 12 C) 13 D) 14 E) 20
let his speed for one half of the journey be 5 miles an hour   let the other half be x miles an hour   now,   avg speed =8 mile an hour   2*5*x/5+x=8   10x=8x+40=&gt;2x=40=&gt;x=20   20
<result>E</result>
It takes Joey the postman 1 hours to run a 5 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?