The graph shows the relationship between the total cost and the number of gift cards that Raj bought for raffle prizes.
A graph titled Cost of Gift Cards. The x-axis shows the number of gift cards, numbered 1 to 9, and the y-axis shows the total cost in dollars, numbered 10 to 90. Blue diamonds appear at points (1, 20), (2, 40), (3, 60), (4, 80).
What would be the cost for 5 of the gift cards?
For each new desk that is purchased, by how much does the amount of money left in the school’s desk fund decrease?