Johny traveled the entire 60 miles trip. If he did the first 6 miles of at a constant rate 24 miles per hour and the remaining trip of at a constant rate 48 miles per hour, what is the his average speed, in miles per hour?
Pick: A) 20mph B) 24mph C) 30mph D) 32mph E) 48mph
Average speed=sum of distance/sum of time. If he travelled the first 6 miles at 24 miles/hr, it would take 0.25 hr. For the remaining trip, if he went at 48 miles/1hr, it would take 1 hour. Then, the average speed is 60miles/(0.25+1)hrs=48miles/1hr.   Therefore, the answer is 48mph.
<result>E</result>
Johny traveled the entire 60 miles trip. If he did the first 6 miles of at a constant rate 24 miles per hour and the remaining trip of at a constant rate 48 miles per hour, what is the his average speed, in miles per hour?