At the movie theatre, child admission is $5.20 and adult admission is $9.60. On Monday, 155 tickets were sold for a total sales of $1070.00. How many adult tickets were sold that day?

We are given that

child admission is $5.20 and

adult admission is $9.60.

Now let us say there were x children and y adults.

On Monday, 155 tickets were sold,

so x+y=155 ... (1)

Total sales were of $1070.00

so 5.20x + 9.60y = 1070 ... (2)

substituting value of x=155-y from equation (1) in equation (2), we get

5.20 (155-y) + 9.60y=1070

806-5.20y+9.60y=1070

4.4y=264

y=60

Answer: 60 adult tickets were sold that day