Math word problem

Question

At the city museum, child admission is $5.40 and adult admission is $8.60. On Saturday, three times as many adult tickets were sold, for a total sales of $904.80 how many child tickets were sold that day ?

Answer 1

number of adult tickets (A) = 3 number of children tickets (C) --> equation 1

A * 8.6 + C * 5.4 = 904.80 --> equation 2

substitute for A from equation 1

3C * 8.6 + C * 5.4 = 904.80

31.2 C = 904.8

C = 29 children tickets

A = 3 * 29 = 87 adult tickets