Question 931052
One plane leaves NYC traveling to LA at 550 mph. At the same time another plane leaves LA for NYC going 650 mph. If the 2 cities are 3000 miles apart how far are the planes from LA when they cross paths?
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dist + dist = 3000
A + B = 3000
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time - time = 0
A/550 - B/650 = 0
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Modify for elimination::
650A - 550B = 0
Divide thru by 50 to get::
13A - 11B = 0
13A + 13B = 13*3000
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Subtract and solve for "B":
24B = 13*3000
B = 1625 miles (distance traveled at 650 mph
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Solve for "A"::
A + B = 3000
A = 3000-1625 = 1375 miles (distance traveled at 550 mph)
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Ans: 1375 miles from LA
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Cheers,
Stan H.