SOLUTION: Erin runs once around the track every 75 seconds. Mark runs around the track once every 90 seconds. If they begin at the same time, in how many seconds will they pass the starting

Question 820997: Erin runs once around the track every 75 seconds. Mark runs around the track once every 90 seconds. If they begin at the same time, in how many seconds will they pass the starting point at the same time?

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Erin runs once around the track every 75 seconds. Mark runs around the track once every 90 seconds. If they begin at the same time, in how many seconds will they pass the starting point at the same time?
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Find the least common multiple:
75 = 3*5^2
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90 = 2*5*3^2
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lcm = 2*3*5^3 = 6*75 = 450
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Ans: after 450 seconds
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Cheers,
Stan H.
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