A motorist travelled to a distant city in 2 hours and returned by another route that is 30 miles longer. On the return trip she travelled 10 miles per hour faster and took 6 minutes longer. Find the length of the shorter route.
Let length of shorter route be D
Then length of longer route = D + 30
Outgoing time: 2 hours, and return time = -----> -----> hrs
We then get the following SPEED equation:
21D = 2(10D + 300) - 420 -------- Multiplying by LCD, 42
21D = 20D + 600 – 420
21D – 20D = 180
D, or length of shorter route =