Question

the graph shows the relationship between the total cost and the number of gift cards that raj bought for raffle prizes. what would be the cost for 5 of the gift cards? $80 $90 $100 $110

Explanation:

Step1: Find the unit rate

From the graph, when \(x = 2\), \(y=40\). The unit rate \(k=\frac{y}{x}=\frac{40}{2} = 20\) (cost per gift - card).

Step2: Calculate the cost for 5 gift - cards

Using the formula \(y = kx\), where \(k = 20\) and \(x = 5\). Then \(y=20\times5=100\)

Answer:

\(\$100\) (the third option)