Ron cycles his way up on a hill side and back. He takes the exact same route both ways. On the trip out he cycles an average speed of 5 miles per hour. On the trip back, downhill cycling at an average speed of 100 miles per hour, he is quick to return back. What is his approximate average speed for the round trip in miles per hour? Choose the correct option
A) 8  B) 9.52  C) 10  D) 11.7  E) 20
Average speed = total distance/total time   Here distance to hill top and back is same as he takes the same route.   D = 5T1 and D=100T2   Therefore, T1 = D/5 and T2 = D/100   T1+T2 = 21d/100   Therefore, average speed = 2d/21d/100 =2d * 100/21d   Answer is 9.52 Since, the options are far away we need not solve till the decimal points   So correct answer is option 9.52
<result>B</result>
Ron cycles his way up on a hill side and back. He takes the exact same route both ways. On the trip out he cycles an average speed of 5 miles per hour. On the trip back, downhill cycling at an average speed of 100 miles per hour, he is quick to return back. What is his approximate average speed for the round trip in miles per hour?