In order to calculate the percentage that enjoy New Years Eve only, we can use the diagram and formula below:
Using F to represent Fourth of July, N to represent New Years Eve and M to represent Memorial Day, the formula is:
From the given data, we have:
P(N) = 28% = 0.28
P(F and N) = 18% = 0.18
P(M and N) = 12% = 0.12
P(all three) = 5% = 0.05
So P(N only) is: