For a saturday matinee, adult tickets cost $5.50 and kids under 12 pay only $4.00. if 70 tickets are sold for a total of $310, how many of the tickets were adult tickets and how many were sold to kids under 12?

20 adults and 50 kids.

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Ax+By=C [Use the standard form of a linear equation]

x+y=C so, x + (C-x) = C [also use this formula]

.

$5.50x+$4.00y=$310 [plug-in the values]

Since x + (C-y) = C, than x+y=70 or x + (70-x) = 70

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5.50x+4.00 (70-x) = 310 [substitute (70-x) for y and simplify]

5.50x+280-4x=310

5.50-4=310-280 [solve for x]

1.5x=30

x=20 adults

and

y = (70-x) = 70-20=50 kids under 12.