Two equations are needed to solve this question.
Let x = the number of adult passes, and y = the number of child passes
1. x + y = 809 passes
2. $80x + $35y = $59095
solve equation 1 for x, which yields x = 809 - y
substitute the value for x in equation 2, which becomes
$80(809 - y) +$35y = $59095
we get $64720 - $80y - $35y = $59095
combining, we get -$45y = -$5625; multiply both sides by -1 to get
$45y = $5625
solving, we get y = 125 passes
subtracting, we get 809 passes - 125 passes = 684 passes
so. our answers are 684 adult passes and 125 child passes
Proof: 684 adult passes times $80/adult pass + 125 child passes times $35/child pass = $59095
$54720 + $4375 = $59095