Question 438775: please help me to solve the problem
places A and B are 100km apart on a highway. one car starts from A and another starts from B . if the cars travel in the same directions with different speed , they meet in 5 hours . if they travel towards each other, they meet in 1 hour. what are the speeds of the two cars
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! places A and B are 100km apart on a highway. one car starts from A and another starts from B . if the cars travel in the same directions with different speed , they meet in 5 hours . if they travel towards each other, they meet in 1 hour. what are the speeds of the two cars
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Catch-up DATA:
A's DATA:
rate = a km/hr ; time = 5 hrs; distance = 5a km
B's DATA:
rate = b km/hr ; time = 5 hrs; distance = 5b km
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Note If A catches up to B, A's distance is 100 km + 5b
So, 5a = 5b+100
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Meeting DATA:
A's DATA:
rate = a km/hr ; time = 1 hr; distance = a km
B's DATA:
rate = b km/hr ; time = 1 hr; distance = b km
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Equation:
a+b = 100 km
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So you have two equations:
5a = 5b+100
a+b = 100
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Modifying those you get:
a-b = 20
a+b = 100
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Add and solve for "a:
2a = 120
a = 60 km/hr (A's rate)
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Solve for "b":
a + b = 100
60 +b = 100
b = 40 mph (B's rate)
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Cheers,
Stan H.
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