Question

Of the 100 entries in a costume contest, 39 entrants were dressed as heroes and 45 entrants were wearing a mask. If 21 entrants were dressed as heroes wearing a mask, how many entrants were neither dressed as heroes nor wearing a mask?

A.37

B.63

C.16

Thank you in advance!

Answer 1

We have 4 types of costume:

A Mask only

B Hero without mask

C Hero with mask

D Neither

A, B, C, D are the numbers of associated people.

A+B+C+D=100

B+C=39

A+C=45

C=21 so B=18 and A=24

And D=100-(24+18+21)=37, so 37 were neither wearing a mask nor dressed as a hero, answer A.