Bunuel
One-third of all U. S. taxpayers may deduct charitable contributions on their federal income tax returns. Forty percent of all taxpayers may deduct state income tax payments from their federal returns. If 55 percent of all taxpayers may not deduct either charitable contributions or state income tax, what portion of all taxpayers may claim both types of deductions?
(A) 3/20
(B) 9/50
(C) 1/5
(D) 7/25
(E) 17/60
Well I see that many people like me are choosing D. It took me almost 10 mins to realize the mistake

So we know that:
Number of taxpayers who deduct charitable contributions = CCd = 1/3
Number of taxpayers who deduct state income tax = SId = 40% = 2/5
Number of taxpayers who dont deduct either = 55/100
=> Number of taxpayers who deduct both = Td = 45/100
Let us assume the overlap between CCd and SId to be x
Applying simple set theory
We know:
CCd + SId - x = Td
1/3 + 2/5 -x = 45/100
If we take the set to be of 100 people,
33 + 40 - x = 45
=> x = 28
=> Portion that can claim both = 28/100 = 7/25 and we assume the correct answer is D
But we make one small mistake in considering 1/3 = 33 whereas it is 33.3333333
So now we need to relook at the below equation:
CCd + SId -x = Td
1/3 + 2/5 - x = 45/100
If we take the set to be of 100 people,
33.3333 + 40 - x = 45
=> x = 28.3333
=> Portion that can claim both = 28.3333/100
Multiple both numerator and denominator by 3
=> Portion = 85/300 = 17/60
which means the correct answer is E.