In an examination, 30% of total students failed in Hindi, 42% failed in English and 28% in both. The percentage of these who passed in both the subjects is :
Choices
A) 23
B) 37
C) 56
D) 40
E) 81

Rationale: "explanation : formula n ( a â ˆ ª b ) = n ( a ) + n ( b ) â ˆ ’ n ( a â ˆ © b ) fail in hindi or english = 30 + 42 â € “ 28 = 44 therefore students who passed = 100 â € “ 44 = 56 . answer : c"
Answer: C