SOLUTION: Two brothers leave from the same point driving in opposite directions, the first brother driving at 55 miles per hour and the second at 70 miles per hour. The first brother has a o

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Question 900850: Two brothers leave from the same point driving in opposite directions, the first brother driving at 55 miles per hour and the second at 70 miles per hour. The first brother has a one-hour head start. How long will they be able to talk if their car phones have a 200-mile range?
I'm not 100% sure on how to set this problem up
RATE X TIME = DISTANCE
Brother A 55 X
Brother B 70 70( -x)
Answer by josgarithmetic(39615) About Me  (Show Source):
You can put this solution on YOUR website!
The question can be restated as, how much time does each brother travel until they are 200 miles apart?

RT=D, uniform rates rule for travel.

The early slow brother travels for 1 hour longer than the fast late brother.
Let t = travel time for the fast late brother.


__________________speed___________time________distance
EarlySlow_________55______________t+1_________55(t+1)
LateFast__________70_______________t__________70t
TOTAL_________________________________________200

The main objective now is solve for t:
highlight%2855%28t%2B1%29%2B70t=200%29

Easily compute t+1 for the early, slow brother.