At the movie theatre, child admission is 5.50 and adult admission is 9.20. On Monday, three times as many adult tickets as child tickets were sold, for a total sales of 662.00 . How many child tickets were sold that day?

Answer is 20 child tickets

Step by step

Let child tickets be “C”
Let adult tickets be “A”

We know
Adult tickets = 3 Child tickets
Equation 1
A = 3C

We know C = 5.50 and A = 9.20 and the total is 662

Equation 2
5.50C + 9.20A = 662

Substitute equation 1 value of A into the equation and solve

5.50C + (9.20)(3C) = 662

5.50C + 27.60C = 662

33.10C = 662

Divide both sides by 33.10 to solve for C

33.10 /33.10 C = 662

C = 20

20 child tickets sold

We can solve for adult tickets and check our work

Equation 1
A = 3C
Substitute C value into equation

A = (3)(20)

Adult tickets = 60

We know C = 5.50 and A = 9.20 and the total is 662

5.50C + 9.20A = 662

(5.50)(20) + (9.20)(60) = 662

110 + 552 = 662

662 = 662

We are correct they equal
Problem solved!!