you can ride a bicycle 15 mph your sister rides 12 mph you g

you can ride a bicycle 15 mph. your sister rides 12 mph. you give her a one hour head start. in how many hours will you catch up if neither of you stops?
Found 2 solutions by Alan3354, stanbon:

Solution

Your DATA:
rate = 15 mph ; distance = x miles ; time = d/r = x/15 hrs.
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Sister\'s DATA:
rate = 12 mph ; distance = x miles ; time = d/r = x/12
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Equation:
her time - your time = 1 hr
x/12 - x/15 = 1
Multiply thru by 60 to get:
5x - 4x = 60
x = 60 miles
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Your time to catch up: x/15 = 60/15 = 4 hrs