At the movie theatre, child admission is $5.90 and adult admission is $9.70 . on tuesday, 168 tickets were sold for a total sales of $1352.20 . how many adult tickets were sold that day?

X= child ticket
y= adult ticket

COST EQUATION:
$5.90x + $9.70y=$1352.20
QUANTITY EQUATION:
x+y=168

Step 1:
Solve for one variable in either equation and substitute it in the other equation

x+y=168

subtract y from both sided
x=168-y

Step 2:
substitute x=168-y in other equation

5.90x + 9.70y=1352.20
5.90(168-y) +9.70y=1352.20

multiply 5.90 by everything in parentheses
(5.90*168)+(5.90*-y) +9.70y=1352.20
991.20-5.90y+9.70y=1352.20

combine like terms
991.20+3.80y=1352.20

subtract 991.20 from both sides
3.80y=361

divide both sides by 3.80
y=95 adult tickets

There were 95 adult tickets sold.

Hope this helps! :)