Question 468272
800 persons are seated on benches of equal length.
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Let original # of benches be "x".
Average persons per bench = 800/x
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If there were 20 fewer benches it would be necessary that two persons more should sit on each bench. find the number of benches.
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Average persons per bench after change:
800/(x-20)
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Equation:
New average - original average = 2
800/(x-20) - 800/x = 2
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800x-800(x-20) = 2
800*20 = 2x(x-20)
800*10 = x^2-20x
x^2-20x-8000 = 0
(x+80)(x-100) = 0
Positive solution:
x = 100 (original # of benches)
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Cheers,
Stan H.
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