SOLUTION: A local concert sells out for their show. They sell all 500 tickets for a total purse of $8,070.00. The tickets were priced at $15 for students (s), $12 for children (c), and $18

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A local concert sells out for their show. They sell all 500 tickets for a total purse of $8,070.00. The tickets were priced at $15 for students (s), $12 for children (c), and $18       Log On


   



Question 1138773: A local concert sells out for their show. They sell all 500 tickets for a total purse of $8,070.00. The tickets were priced at $15 for students (s), $12 for children (c), and $18 for adults (a). If the band sold three times as many adult tickets as children’s tickets, how many of each type was sold?

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


This problem can be a good example for comparing the method of solving the problem with three variables (as suggested by the statement of the problem) to the method of solving it with a single variable.

While it is important to know how to solve a problem involving a system of equations in several variables, very often the amount of effort required to solve the problem is far less with a single equation in one variable.

A solution using 3 variables....

c = number of children's tickets
s = number of student tickets
a = number of adult tickets

(1) a%2Bs%2Bc+=+500 the total number of tickets was 500
(2) a+=+3c the number of adult tickets was 3 times the number of children's tickets
(3) 12c%2B15s%2B18a+=+8070 the total cost of the tickets was $8070

Substitute (2) in (1) and (3) to eliminate a, giving two equations in s and c:

(4) 3c%2Bs%2Bc+=+500 --> s%2B4c+=+500
(5) 12c%2B15s%2B18%283c%29+=+8070 --> 15s%2B66c+=+8070

Eliminate s between (4) and (5) by multiplying (4) by -15 and adding:

-15s-60c+=+-7500
15s%2B66c+=+8070
6c+=+570
c+=+95

The number of children's tickets was c = 95.

Then the number of adult tickets was 3c = 285.

The total number of adult and children's tickets was 95+285 = 380; so the number of student tickets was 500-380 = 120.

ANSWER: 95 children's tickets, 120 student tickets, 285 adult tickets.

A solution using one variable....

let x = number of children's tickets
then 3x = number of adult tickets (3 times as many as children's)
and (500-4x) = number of student tickets (the total of 500, minus the adult and children's tickets)

The total cost was $8070:

12x%2B15%28500-4x%29%2B18%283x%29+=+8070
12x%2B7500-60x%2B54x+=+8070
6x+=+570
x+=+95

ANSWER:
children: x = 95
students: 500-4x = 500-380 = 120
adults: 3x = 285