SOLUTION: Jason and Kim were at the park. If they both left at the same time, and Jason was driving at 30 mph, and kim was driving at 40 mph in the opposite direction, how long will it be b

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Jason and Kim were at the park. If they both left at the same time, and Jason was driving at 30 mph, and kim was driving at 40 mph in the opposite direction, how long will it be b      Log On

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Question 333545: Jason and Kim were at the park. If they both left at the same time, and Jason was driving at 30 mph, and kim was driving at 40 mph in the opposite direction, how long will it be before they are 210 miles apart?
Answer by jrfrunner(365) About Me  (Show Source):
You can put this solution on YOUR website!
You need to understand the relationship:
d=r*t (distance = rate*time)
----
Kim's distance after t hours: d%5Bk%5D=40%2At
Jason's distance after t hours: d%5Bj%5D=30%2At
--
They are travelling in opposite directions and you need to know the time when they are 210 miles apart, so add their distances
--
210+=+d%5Bk%5D%2Bd%5Bj%5D=40%2At+%2B+30%2At+
210=70%2At
210/70 =t
===
t = 3 hours