Question 576080: For her workout, Sarah walks north at the rate of 2 mph and returns at the rate of 4 mph. How many miles does she walk if the round trip takes 3.5 hours? (Enter your answer as a decimal rounded to the nearest tenth of a mile.) Answer by solver91311(18785) (Show Source):
Generally it is a good idea to assign the variable in a word problem to the value you are trying to calculate, but this problem is an exception. Let represent the one-way distance and we'll double it later to get the answer.
Distance equals rate times time, so time is equal to distance divided by rate. The time it takes for the outbound trip is then:
and the time it takes for the inbound trip is:
And the sum of these two times is the 3.5 hours it took for the round trip:
Solve for and then calculate to get the desired answer.
My calculator said it, I believe it, that settles it