Answer:
a. 3
Step-by-step explanation:
We solve this question gathering the information given in the question.
June serves 8 guests slices of both pies.
This is soon going to be used
June serves a total of 10 slices of apple pie
This includes the 8 guests which got served both pieces. So 10 - 8 = 2 guests were served only apple pie.
11 slices of blueberry pie.
By the same logic as above, 11 - 8 = 3 guests were served only blueberry pie.
So
8 + 2 + 3 = 13 guests were served at least one pie.
16 - 13 = 3 guests had no pie at all.