Proportion

[phoenix9801]

Hi is this the best to solve the problem by using the answer choices ? If So is the answer C???? Thanks.


Stacy needs to be at dinner at her parents' house at 7:00pm. Her parents are 210 miles away and her car travels at an average speed of 60 miles per hour. What time does she need to start driving?


A) 3:00pm
B) 3:30pm
C) 4:00pm
D) 4:30pm
E) 5:30pm

[digvijayk]

210/60 = 3.5 => 3.5 hours.
So to reach by 7, start at 3:30.

IMO B.

[Anurag@Gurome]

First of all this problem has nothing to do with proportion. This is a simple rate and work problem.

Stacy needs to travel 210 miles at 60 miles per hour speed.
Hence, Stacy will take (210/60) = 3.5 hours = 3 hours 30 minutes

Hence, to reach her destination at 7:00PM, Stacy need to start by (7:00PM - 3 hours 30 minutes) = 3:30PM

The correct answer is B.