At the movie theatre, child admission is $5.20 and adult admission is $8.40 . On Sunday, 170 tickets were sold for a total sales of $1172.00 . How many child tickets were sold that day?
total # of tickets = # of kids + # of adults, or 170 = k + a total money made = price of a kid's ticket*# of kids tickets + price of an adults ticket*# of adult tickets, or $1172.00 = $5.20k + $8.40a Rewrite the first equation. 170 = k + a a = 170 - k Plug the first equation into the second. 1172 = 5.2k + 8.4(170 - k) 1172 = 5.2k + 1428 - 8.4k -256 = -3.2k k = 80 tickets