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Question 981814: a car leaves a place traveling 30 kilometers per hour. an hour later a second car leaves place A following the first car , traveling 50 kilometers per hour. how many hours after leaving place a will it take the second car to over take the first?
Found 3 solutions by JulietG, josgarithmetic, Alan3354:
Answer by JulietG(1812)   (Show Source):
You can put this solution on YOUR website! After an hour, car A has gone 30km, car B has gone 0
After 2 hours, car A = 60, car B = 50
After 2.5 hours, car A = 75, car B = 75
Answer by josgarithmetic(39630)  (Show Source):
You can put this solution on YOUR website! This type of travel uniform rates problems is common.
r, speed of slow car
R, speed of fast car
k, how much time that slow car travels before fast car begins same direction from common departure location
t, travel time of the fast car
d, distance that both cars traveled to same point on the route
GIVEN VALUES FOR VARIABLES
___________________speed____________time__________distance
SLOW-early__________r_______________t+k___________d
FAST-late___________R________________t____________d
Note again, both cars will reach the same distance d, and unknown variable; but we can still solve for the other unknown, t.
 , because the two cars go the same distance when fast car overtakes slow car.
You KNOW that  will be negative and that  is also negative so multiply left and right by  ...
 , time in hours for fast late car to overtake the slow early car.
Substitute the given values and evaluate t.
Answer by Alan3354(69443)  (Show Source):
You can put this solution on YOUR website! a car leaves a place traveling 30 kilometers per hour. an hour later a second car leaves place A following the first car , traveling 50 kilometers per hour. how many hours after leaving place a will it take the second car to over take the first?
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In 1 hour, the 1st car is 30 kms away.
The 2nd cars "gains on it" at 20 km/hr (50-30)
30/20 = 1.5 hours.
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