Without taking a single break, mercedes hiked for 10 hours, up a mountain and back down by the same path. While hiking, she averaged 2 miles per hour on the way up and 3 miles per hour on the way down. How many miles was it from the base of the mountain to the top?

Answer 1

time = distance/speed.
add up the times:

d/2 + d/3 = 10
d = 12