For a class play, student tickets cost $2 and adult tickets cost $5. A total os 30 tickets were sold. If the total sales must exceed $90, what is the miniuim number of adult tickets that must be sold?

Answer 1

Let s = # student tickets and a = # adult

s = 30 - a

2s + 5a > 90

Substitute 30-a for s in second equation and solve for a. Insert that value into the first equation and solve for s. Check by inserting both values into the second equation.