Question 681941: I need help with Linear systems word problems. Onf question that I am having trouble with is:
One plane at 520 feet is ascending at a rate of 40 feet per minute, while another plane at 3800 feet is desending at a rate of 120 feet per minute. How long will it take the two planes to be at the same altitude?
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! One plane at 520 feet is ascending at a rate of 40 feet per minute, while another plane at 3800 feet is desending at a rate of 120 feet per minute. How long will it take the two planes to be at the same altitude?
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h(t) = 520 - 40t = 3800 - 120t
520 - 40t = 3800 - 120t
80t = 3280
t = 41 minutes
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but,
the first plane will hit the ground in 13 minutes, the 2nd will impact at 31.67 minutes.
So they'll be at the same altitude, zero, at 31.67 minutes.
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