
Kendra F. answered 09/25/16
Tutor
4.7
(23)
Patient & Knowledgeable Math & Science Tutor
Let;
a = cost of adult ticket
c = cost of child's ticket
Three adults and four children must pay $ 115
3a + 4c = 115
Two adults and three children must pay $ 82
2a + 3c = 82
Now solve for one of the variables in either equation
2a + 3c = 822a = 82 - 3c
a = (82 - 3c)/2
Substitute this into the other equation and solve for c, the cost of a child's ticket
3a + 4c = 115
3(82 - 3c)/2 + 4c = 115
123 - 9c/2 + 4c = 115
combine like terms
123 - 115 = 9c/2 - 8c/2
8 = c/2
16 = c
Use the cost of a child's ticket to solve for a, cost of adult ticket.
3a + 4(16) = 115
3a + 64 = 115
3a = 115 - 64
3a = 51
a = 17