Solution: Let [tex]x[/tex] be the number of adult ticket's.
The number of child ticket [tex]=2x+12[/tex]
We are given, that an adult ticket cost's $10 and child ticket costs $6. Also the church luncheon made $842.
Therefore,
[tex]x \times 10 + (2x+12)6=842[/tex]
[tex]10x+12x+72=842[/tex]
[tex]22x=842-72[/tex]
[tex]22x=770[/tex]
[tex]x=\frac{770}{22}=35[/tex]
Therefore, the number of adult ticket's sold = 35
And the number of child ticket's sold = 2 x 35 + 12 = 70 + 12 = 82
