In an examination, 35% of total students failed in Hindi, 45% failed in English and 20% in both. The percentage of these who passed in both the subjects is :
10%
20%
30%
40%
Explanation:
Formula n(a?b) = n(a) + n(b) - n(anb)
Fail in Hindi or English = 35 + 45 - 20 = 60
Therefore students who passed = 100 - 60 = 40.