How would you solve?
A bicyclist travels uphill from town A to town B for 2 hours at an average speed of 4 miles per hour and returns along the same road at an average speed of 6 miles per hour. What is the bicyclist’s average speed for the round trip, in miles per hour?
a) 4 4/5
c) 5 1/5
d) 5 2/5
e) 5 3/5
This kind of problems(rate problems are explained in details in MGMAT Word Translations
U should not just find the average of two given speed rates, the average speed is found by dividing the total distance by the total time to travel the distance.
First find the distance traveled by byciclist to town B S=t*v (t-time, v-speed) S = 2*4=8
now find the time spent for coming from b to a, t=S/v or t=8/6
So now Total time he spent in his trip to and from A is 2+(4/3) or 10/3
Total distance of trip is 2*8 or 16
so the average speed he travelled is 16/(10/3) or 4 4/5, A