Question 1114919
To solve as a system of equations:
Equation for the number of tickets sold:
a + s = 584 
multiply all elements in this equation times 5:
5a + 5s = 2920 (1)
Equation for the total $ tickets sold:
5a + 3s = 2112 subtract this equation from (1):
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5a + 5s = 2920
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5a + 3s = 2112
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0a + 2s = 808
rewrite, since the value of a is 0:
2s = 808
s = 404