Answer:
The correct option is $2.50.
Explanation:
This can be determined by calculating the change in total cost of lunch using the data given in the question as follows:
Slice of pizza Total cost of lunch ($) Change in total cost of lunch ($)
0 7.5 -
1 10 2.5
2 12.5 2.5
3 15 2.5
4 17.5 2.5
5 20 2.5
6 22.5 2.5
7 25 2.5
8 27.5 2.5
Since the change in total cost of lunch in table abov is constant at $2.50, this implies that for each additional slice of pizza that is purchased, the total cost of lunch increases by $2.50.
Therefore, the correct option is $2.50.