At the movie theatre, child admission is $6.50 and adult admission is $9.80. On Saturday, 153 tickets were sold for a total sales of $1222.20. How many child tickets were sold that day?

C + A = 173

6.50 * C + 9.80*A = 1368.70

Solves the first equation for C and multiplies the second equation by 10 to clear the decimals:

C = 173 - A

65C + 98A = 13687

65 (173 - A) + 98A = 13687

11245 - 65A + 98A = 13687

33A + 11245 = 13687

33A = 13687 - 11245

33A = 2442

A = 74

C = 99