Shelby sold 75 raffle tickets for the school fundraiser over a 3-year period. If Kelly sold 15 less tickets than Shelby over the last 3 years, how many did Kelly sell each year on average?

20 tickets

Step-by-step explanation:

From the question, we are informed that Shelby sold 75 raffle tickets for the school fundraiser over a 3-year period while Kelly sold 15 less tickets than Shelby. This means that the number of tickets sold by Kelly is:

= 75 - 15

= 60 tickets

The number of tickets sold by Kelly each year on average will be:

= Number of tickets sold / Number of years.

= 60/3.

= 20 tickets

over the last 3 years