A group of 19 students want to see the show at the planetarium. The tickets cost $11 for each student who is a member of the planetariums frequent visitor program and $13 for each student who is not a member. The total cost of the students' tickets is $209.

Let x represent the number of students in the group who are members of the frequent visitor program. Write an expression in terms of x for the number of students in the group who are not members. Then write an equation to determine the value of x.

If the amount of members are y, then the total number of people who attend is x+y=19. In addition 11*y (since it costs 11 dollars per member)+13*x=209. Subtracting x from both sides in the first equation, we get y=19-x. Plugging that into the second equation, we get (19-x)*11+13*x=209. Multiplying it out, we get 201-11x+13x=209. Subtracting 201 from both sides, we get 2x=8 and by dividing both sides by 2 we get x=4

Answer Link