A survey was taken among 100 brainiacs. Of those surveyed, twice as many brainiacs likerebus teasers as math teasers. If 18 brainiacs like both rebus teasers and math teasers and 4like neither kind of teaser, how many brainiacs like math teasers but not rebus teasers?	Choose the correct option
A) 17  B) 18  C) 19  D) 20  E) 21

Rationale: let x brainiacs like only rebus teasers and y brainiacs like only math teasers . now , x + y = 100 - 18 - 4 = 78 . also given that , x + 18 = 2 ( y + 18 ) x = 2 y + 18 . 78 - y = 2 y + 18 3 y = 60 y = 20 so 20 brainiacs like math teasers but not rebus teasers answer : d
Answer: D