Answer:
39 child tickets
Explanation:
Let x represent the number of child tickets sold,
let y represent the number of adult tickest sold.
"three times as many adult tickets as child tickets were sold," becomes
x = y/3 x is one-third the value of y
"$5.80 and adult admission is $9.20" and " for a total sales of $1,302.60" become
$5.80x + $9.20y = $1,302.60
We know that x = y/3, so substitute that into the second equation...
$5.80(y/3) + $9.20y = $1,302.60
Now solve for y...
$5.80y + $27.60y = $3,907.80 (multiply by 3 to get rid of the fraction)
$33.40y = $3,907.80 (combine like terms)
y = $3,907.80/$33.40 (divide both sides by $33.40 to isolate y)
y = 117
If there were 117 adult ticket sold, then there were
x = 117/3 child tickets
x = 39 child tickets