Answer:
An adult ticket is 17
A childs ticket costs 12 dollars
Explanation:
Let a = adult price
c = child price
3a + 4c = 99
2a + 3c = 70
Multiply the first equation by 2
2(3a + 4c) = 99*2
6a + 8c = 198
Multiply the second equation by -3
-3 (2a + 3c) = 70*-3
-6a -9c = -210
Add these new equations together
6a + 8c = 198
-6a -9c = -210
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-c = -12
Multiply by -1
c = 12
A childs ticket costs 12 dollars
Now we need to find the price of an adult ticket
2a + 3c = 70
2a + 3(12) = 70
2a +36 = 70
Subtract 36 from each side
2a +36-36 =70-36
2a = 34
Divide by 2
2a/2 = 34/2
a = 17
An adult ticket is 17