Question 288667
Let x = # of Adult Tickets

8.75x + 5.5(3x) = 176.75
8.75x + 16.5x = 176.75
25.25x = 176.75
{{{x = highlight(7)}}}

Substitute back into original question:
8.75 * 7 = 61.25
5.50 * 21 = 115.50
61.25 + 115.50 = 176.75