A total of 150 tickets were sold for the annual concert. Student tickets were $4 and non-students $8. If the total revenue was $840, how many tickets of each type were sold ?

x = 90

y = 60

Step-by-step explanation:

Let x = student

Let y = non-student

x + y = 150

4x + 8y = 840 <—— Use elimination/addition ethos for both equations

8 (x + y = 150)

-1 (4x + 8y = 840) <—— Let’s eliminate y

8x + 8y = 1200

+ -4x - 8y = -840

—————————————

4x = 360

x = 90

x + y = 150 <— substitute for x from above

90 + y = 150

- 90 = - 90 <— subtract from both sides

y = 60

14

step-by-step explanation: