You sell tickets for admission to your school play and collect a total of $104. Admission prices are $6 for adults and $4 for students. You sold 21 tickets. How many student tickets did you sell ?​

11 tickets

Step-by-step explanation:

1. write an equation:

First,  variable x symbolizes the number of adults who bought tickets. And variable y symbolizes the number of students.

If each adult paid $6, and each student paid $4, and the total dollars you've collected is 104, this is how we'll write our equation:

6x + 4y = 104

2. we can write another equation based on this information: "You sold 21 tickets". Which concludes that the number of tickets adults and students had paid for equals the number of tickets you've sold:

x + y = 21

3. now, we've got two equations. Let's compensate:

x + y = 21

x = 21 - y

6x + 4y = 104

6 (21 - y) + 4y = 104

126 - 6y + 4y = 104

-6y + 4y = -22

-2y = -22

y = -22 / -2

y = 11

So the number of student tickets is 11.