math question?

Jen Butler has been pricing​ Speed-Pass train fares for a group trip to New York. Three adults and four children must pay $102.  Two adults and three children must pay $72.  Find the price of the​ adult's ticket and the price of a​ child's ticket.

BeeLiz192017-09-14T03:35:29Z

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Let x be the amount of each ticket for an adult.
Let y be the amount of each ticket for a child.

three adults at x value AND four children at y value IS 102

3x + 4y = 102

two adults at x value AND three children at y value IS 72

2x + 3y = 72

Rearrange one of the equations to solve for a variable:

2x + 3y = 72

3y = -2x + 72

y = -2/3x + 24

Now we can plug this new equation into the one we haven't touched yet:

3x + 4y = 102

3x + 4(-2/3x + 24) = 102

3x - 8/3x + 96 = 102

9/3x - 8/3x = 102 - 96

1/3x = 6

Dividing by 1/3 is the same as multiplying by 3/1:

x = 18

Plug this into the equation solving for y:

y = -2/3x + 24

y = -2/3(18) + 24

y = -36/3 + 24

y = -12 + 24

y = 12


THEREFORE adult tickets cost $18 and kids tickets cost $12.

?2017-09-14T00:46:31Z

3A+4C = 102
2A+3C = 72
3A+4.5C = 108
0.5C = 6
C = $12
A = $18