Im reviweing what I learned last year, can you tell me what the answer is, and possibly explain how to get the answer :

Two cars start from the same point and travel in opposite directions at rates differing by 10 mph. If the cars are 240 miles apart after 3 hours, how fast is the slower car traveling?

A 45mph
B 40 mph
C 35 mph
D 43 mph

I learned how to do this, but i forget!!

THANKS!


I am doing this extra work tog et in an advanced school. I tried other sections, but got no answers, I was thinking maybe some of you teens would be able to answer it....