9514 1404 393
Answer:
- 7 adult tickets
- 9 child tickets
Explanation:
Using the variables defined in the problem statement, we can write the equations ...
a + c = 16 . . . . . . . . . . . . number of tickets bought
10.50a +7.50c = 141 . . . cost of tickets bought
Substituting for c in the second equation, we get ...
10.50a +7.50(16 -a) = 141
3.00a +120 = 141 . . . . . . . . simplify
3a = 21 . . . . . . . . . . . subtract 120
a = 7 . . . . . . . . divide by 3
16 -a = c = 9 . . . . . . . find the number of child tickets
They bought 7 adult tickets and 9 child tickets.
_____
If you examine the solution, you see that the number of adult tickets (the higher priced item) is the quotient of the difference between the actual expenditure (141) and the amount that would have been spent on all child tickets (16×7.50=120), and the difference in ticket prices (10.50-7.50=3.00). Knowing this, you can often work problems of this kind in your head.