total ? of tickets = y of kids + x of adults or 170 = k +a
The money altogether = how much a kid's ticket costs y of kid's tickets + how much an adults ticket costs x of adults tickets
Or: $1172.00 = $5.20 + $8.40a
REWRITE:
170= k + a
a =170 - k
Add the first equation in the second equation.
1172 = 5.2k + 8.4 (170 - k)
1172 = 5.2k + 1428 - 8.4k
-256 = -3.2k
k= 80 tickets
Hope this helps!-Aparri