Question 1180809:  A movie theater has a seating capacity of 129. The theater charges $5.00 for children, $7.00 for students, and $12.00 for adults. There are half as many adults as there are children. If the total sales was $930, how many children, students and adults attended? 
 Found 2 solutions by  ikleyn, josgarithmetic: Answer by ikleyn(52903)      (Show Source): 
You can  put this solution on YOUR website! . 
A movie theater has a seating capacity of 129.  
The theater charges $5.00 for children, $7.00 for students, and $12.00 for adults.  
There are half as many adults as there are children.  
If the total sales was $930, how many children, students and adults attended? 
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Let x be the number of adults.
Then the number of children is 2x, according to the condition,
and the number of students is the rest (129-x-2x) = (129-3x).
The "money" equation (the revenue equation) is
    12x + 5*(2x) + 7*(129-3x) = 930  dollars.
    12x + 10x + 7*129 - 21x = 930
    x = 930 - 7*129 = 27  is the number od adults.
ANSWER.  27 adults;  2*27 = 54 children and the rest (129-27-54) = 48 are students.
 
Solved.
 
 
The lesson to learn from the solution is THIS :
 
 
     This problem is to be solved using ONE unknown and one equation - not three.
 
 
 Answer by josgarithmetic(39630)      (Show Source): 
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