SOLUTION: Roberto left his parent's house at 11 A.M. traveling at an average rate of 30 mph. His parents left their house at 12 P.M. traveling at an average rate of 45 mph going the same way

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Question 1048247: Roberto left his parent's house at 11 A.M. traveling at an average rate of 30 mph. His parents left their house at 12 P.M. traveling at an average rate of 45 mph going the same way as Roberto so that they could catch up to him. After how many hours will it take Roberto's parents to catch up to him? How to set up equation.

Found 2 solutions by ewatrrr, addingup:
Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website!
distance traveled by both Roberto and his Parents is equal
30t = 45(t-1)
45 = 15t
t = 3hr
(t-1) = 2hr, hours will it take Roberto's parents to catch up to him

Answer by addingup(3677) (Show Source):
You can put this solution on YOUR website!
t*30 = (t+11)45 <--- t+1 because they left an hour later, so to make it equal to the left side, to Roberto, we have to add the one hour.
30t = 45t-45
-15t = 45 divide both sides by -15, and remember -/- = +
t = -3 Roberto drove 3 hours before his parents caught up with him.
>>>>>>>>>>>>>>>>>>>>>>>
Check:
In 3 hours R would have gone from 11am to 2pm. 3 hours at 30 = 90
The parents started at 12. At 2pm they would have driven 45*2 = 90
As you see, at 2 pm they both met after driving the same distance, 90 miles.