Answer:
75/4 cups (or 18-3/4 cups)
Step-by-step explanation:
Ignore all the wording about glue, baking soda and saline.
What this question reduces to is that the recipe for :
2 people ---> requires 3 3/4 cups (or 15/4 cups) of shaving cream
10 people ----> requires 5 times the amount of shaving cream needed for 2 people
Hence shaving cream needed for 10 people
= 5 x 3 3/4 cups
= 5 x 15/4 cups
= 75/4 cups (or 18-3/4 cups)