SOLUTION: Please help! A room contains 78 chairs arranged in rows. The number of rows is one more than twice the number of chairs per row. Find the number of rows.

Question 953527: Please help!
A room contains 78 chairs arranged in rows. The number of rows is one more than twice the number of chairs per row. Find the number of rows.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A room contains 78 chairs arranged in rows. The number of rows is one more than twice the number of chairs per row. Find the number of rows.
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Let the number of rows be "r".
Let the number of chairs in a row be "c"
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Equations:
c*r = 78
r = 2c+1
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Substitute for "r" and solve for "c":
c(2c+1) = 78
2c^2 + c - 78 = 0
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Factor:
(c-6)(2c+13) = 0
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Positive solution:
# of chairs in a row = 6
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Solve for "r":
r = 2c+1
# of rows = 2*6+1 = 13
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Cheers,
Stan H.
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