Answer:
- adult tickets: $13
- student tickets $7
Step-by-step explanation:
The given equations are ...
4a +5s = 87
2a +2s = 40
We observe that the coefficient of 'a' in the first equation is 2 times that in the second equation. We can multiply the second equation by -2 and add it to the first to eliminate 'a' terms.
(4a +5s) -2(2a +2s) = (87) -2(40)
4a +5s -4a -4s = 87 -80 . . . . . . . . . eliminate parentheses
s = 7 . . . . . . . . . . . . . . . . . .simplify
2a +2(7) = 40 . . . substitute for s in the second equation
2a = 26 . . . . . . subtract 14
a = 13 . . . . . . . divide by 2
Adult tickets cost $13; student tickets cost $7.
