Question

Select the correct graph and equation. A local volunteer group has 150 raffle tickets to sell. They sell them in packs of three tickets per customer. Determine which graph and which equation represent the number of tickets, T, the group has left after selling tickets to c customers.

Answer 1

The equation for the number of tickets remaining, T, after selling to c customers is: T = 150 − 3c or T = -3c + 150. This represented by graph 2

How do we form the equation and identify the graph?

To find the equation

• the number of tickets T
• c customers,

Each customer buys 3 tickets, so the number of tickets sold after c customers would be 3c.

Thus, the equation for the number of tickets remaining, T, after selling to c customers is: T=150−3c

Point on the graph

When c=0

T = 150−3(0) = 150. Point 1 (0, 150)
T = 150 − 3(10) = 150−30 = 120. Point 2 (10, 120)
T = 150 − 3(50) = 150 - 150 = 0. Point 3 (50, 0)