A man walks from B to C, a distance of x miles, at 10 miles per hour and returns at 15 miles per hour. What is his average speed?	Answers
A) 10 mph  B) 12 mph  C) 8.8 mph  D) 8.4 mph  E) 14 mph
Total distance covered = 2x   Time taken12miles / hour = x/15 hrs   Time taken @ 8 miles / hour = x/10 hrs   Avg speed = 2x / (x/10 + x/15) = 12 mph   Ans is 12 mph
<result>B</result>
A man walks from B to C, a distance of x miles, at 10 miles per hour and returns at 15 miles per hour. What is his average speed?