Elena went on a 6-mile walk. She completed the first half of the walk 1 mi/h faster than usual and the second half of the walk 2 mi/h slower than the first half.

a. If it took her 7 .2 h to complete the walk, what is her usual rate?
b. What is the formula necessary to solve this problem?

1 answer

if her usual speed is x, then since time = distance/speed,
3/(x+1) + 3/(x-1) = 7.2