9514 1404 393
Answer:
- -3 adult tickets were sold
- 18 children's tickets were sold
Explanation:
Using the first equation to write an expression for y, we get ...
y = 15 -x
Substituting that into the second equation gives ...
30x +20(15 -x) = 270
10x +300 = 270 . . . . . . . . . simplify
10x = -30 . . . . . . . . . . . . . subtract 300
x = -3 . . . . . . . . . . . . . . divide by 10
y = 15 -(-3) = 18 . . . . find the corresponding value of y
The number of adult tickets sold is -3; the number of children's tickets sold is 18.
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Additional comment
If 15 tickets were sold for 270 the way your problem statement says, then the average ticket price is 270/15 = 18 per ticket. You show the ticket prices to be 20 for children and 30 for adults. That is, the average price is expected to be between 20 and 30. There is something wrong with this problem.