Answer: 33 child tickets that were sold.
Step-by-step explanation:
Let x represent the number of child tickets that were sold.
Let y represent the number of adult tickets that were sold.
At the city museum, child admission is $5.40 and adult admission is $9.10. A total sales of $1079.10 was made on Monday. This means that
5.4x + 9.1y = 1079.1 - - - - - - - - - -1
On Monday, three times as many adult tickets as child tickets were sold. This means that
y = 3x
Substituting y = 3x into equation 1, it becomes
5.4x + 9.1 × 3x = 1079.1
5.4x + 27.3x = 1079.1
32.7x = 1079.1
x = 1079.1/32.7
x = 33
y = 3x = 3 × 33
y = 99
