word problem--If car A is going 50mph and is 15miles ahead of car B who is going 60mph, how long will it take car B to catch up with other?

50x+15=60
-15=15
50x=45
x=10
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3 answers

You don't define what your x is, so your equation makes no sense to me.
The left side of your equation has units of distance, while your right side is speed, thus it is gibberish.

If x is the time needed
the distance covered by the slower car = 15 + 50x
the distance covered by the faster car = 60x
So
60x = 50x + 15
10x = 15
x = 1.5 hours.

check:
slower car went 15 + 1.5(5) = 90 miles
faster car went 1.5(60) = 90 miles
well, how about that , the went the same distance !
so it would take over an hour for car b to catch up with car a.

the choices given on the study guide are 10 min, 15 min, 40 min, 60 min or none of these
well, I guess you know which is the correct choice, eh?

consider it this way. car A is 15 miles ahead when car B starts. B is only going 10 mi/hr faster than A, so it will take 15/10 hours to make up the difference. As Reiny showed, that means it takes 1.5 hours.