math.
posted by vincent .
Mr. B walks for 4 hours at the rate of y miles an hour. He stops an hour for lunch and then returns to the starting point by a route that is twice as long, but he travels in an auto whose speed is five times that of his walking rate. Find the number of hours spent on the entire trip.

Distance covered in 4 hrs=4y
Return distance=2x4y=8y and speed=5y Hence time of return trip=8y/5y=1.6hr
Halt=1hr
Total time=4+1+1.6=6.6hrs