Answer:
$8
Step-by-step explanation:
Let a and s represent the prices of adult and student tickets, respectively. The relations described by the problem statement can be written ...
9a +13s = 212
4a +15s = 168
Using Cramer's method, we can find the value of s to be ...
s = (212·4 -168·9)/(13·4 -15·9) = -664/-83 = 8
The price of a student ticket is $8.
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Comment on Cramer's method
For the equations ...
the solutions can be written as ...
This method is useful when the equation's coefficients don't lend themselves to "nice" arithmetic or when the value of only one variable is needed (as here).
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If you look up "Cramer's Method" in Wikipedia or other sources, you will likely find that the signs of the differences are reversed. That is, ...
x = (ce-bf)/(ae-bd)
This makes no difference to the result of the calculation. The variable ordering shown here can be remembered as a pattern of Xs when compared to the locations of the coefficients in the given equations. Often, this permits the problem to be completely solved mentally.
