SOLUTION: Elaina bicycles 4km/h faster than Robert. In the same time it takes Robert to bicycle 30 km, Elaina can bicycle 42 km. How fast does each bicyclist travel?

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Question 429891: Elaina bicycles 4km/h faster than Robert. In the same time it takes Robert to bicycle 30 km, Elaina can bicycle 42 km. How fast does each bicyclist travel?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Elaina bicycles 4km/h faster than Robert. In the same time it takes Robert to bicycle 30 km, Elaina can bicycle 42 km. How fast does each bicyclist travel?
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Robert DATA:
rate = x km/h ; dist = 30 km ; time = 30/x hr
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Elaina DATA:
rate = (x+4)km/h ; dist = 42 km ; time = 42/(x+4) hr
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Equation:
time = time
30/x = 42/(x+4)
30(x+4) = 42x
12x = 120
x = 10 km/h (Robert's rate)
x+4 = 14 km/h (Elaina's rate)
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Cheers,
Stan H.
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