Answer:
• A(r)=5+2(r-1)
,
• $19
,
• 6 tickets
Step-by-step explanation:
Cost of the first raffle ticket = $5.
Cost of each raffle ticket after that =$2.
A function to show how much money r amount of raffle tickets cost will therefore be:

Cost of 8 raffle tickets

Number of tickets that can be bought for $15

6 raffle tickets can be bought with $15.