Question

the graph below shows the total cost for lunch, c, when will and his friends buy a large salad to share and several slices of pizza, p. for each additional slice of pizza that is purchased, by how much does the total cost of lunch increase? $1.50 $2.00 $2.50 $3.00

Explanation:

Step1: Identify two points

Take two points from the graph, e.g., when \( p = 1 \), \( c = 10 \); when \( p = 2 \), \( c = 12.5 \)? Wait, no, better to take clear points. Let's see, when \( p = 0 \), \( c = 7.5 \)? Wait, no, the first point (p=0) is around 7.5? Wait, maybe better to take p=1, c=10; p=2, c=12.5? No, maybe the grid: each square is 5? Wait, the y-axis is 5,10,15,20,25,30,35,40. The x-axis is 1,2,3,4,5,6,7,8. Let's take two points: (1,10) and (2,12.5)? No, maybe (1,10) and (3,15). Wait, when p=1, c=10; p=3, c=15. Then the slope (increase per slice) is \( \frac{15 - 10}{3 - 1} = \frac{5}{2} = 2.5 \)? Wait, no, maybe another pair. Wait, (0, 7.5) and (1, 10): slope is 2.5. Or (2,12.5) and (4,17.5): slope is \( \frac{17.5 - 12.5}{4 - 2} = \frac{5}{2} = 2.5 \). So each additional slice increases cost by $2.50.

Step2: Confirm with another pair

Take (5,20) and (6,22.5): \( \frac{22.5 - 20}{6 - 5} = 2.5 \). So the increase per slice is $2.50.

Answer:

\$2.50 (Option: \$2.50)