Mischa drove from A to B, a distance of 100 miles, at an average speed of 50 miles per hour, and then back from B to A along the same route at an average speed of m miles per hour. What is the value of m?
(1) Mischa's average speed for the entire round trip, excluding any time he spent at point B, was (m+50)/2 miles per hour.
(2) If Mischa's average speed from B to A had been 20% slower, the total time for the entire round trip, excluding any time Mischa spent at point B, would have been 12.5% greater.
(1) Mischa's average speed for the entire round trip, excluding any time he spent at point B, was (m+50)/2 miles per hour.
(2) If Mischa's average speed from B to A had been 20% slower, the total time for the entire round trip, excluding any time Mischa spent at point B, would have been 12.5% greater.
Last edited by abhasjha on Mon Jul 28, 2014 2:20 am, edited 1 time in total.
