9514 1404 393
Answer:
15x +5y = 85 . . . . . equation for money spent
Step-by-step explanation:
The money spent will be the sum of products of numbers of tickets and their cost:
15x +5y = 85
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The number of tickets bought will be the sum of the numbers of each kind.
x +y = 13
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The solution of this system of equations is (x, y) = (2, 11).