A + c = 824 represents number of tickets to sell
20a + 12c = 13,344 represents cost of each type of ticket
multiply equation 1 by -12 to cancel the variable 'c' and solve for 'a'
-12(a + c = 824)
-12a - 12c = - 9888
20a + 12c = 13,344 add equations together
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8a = 3456 divide both sides by 8
a = 432
To find children's tickets substitute adult numbers back into equation 1.
a + c = 824
432 + c = 824
subtract 432 from both sides
c = 392
adult 432, children 392
81.42
= 81+ 0.42
= 81+ 42/100
= 81+ (42/2) / (100/2)
= 81+ 21/50
= 81 21/50
The final answer is 81 21/50~
20× 8 = 160
160 + 2x > or = 500
-160--------------- -160
2x > or = 340
÷2------------÷2
x > or = 170
She has to sell at least 170 cupcakes to make $500 in profit.
Hope this helps!
