Question

In an examination, $35$% students failed in Hindi, $45$% students failed in English and $20$% students failed in both the subjects. What is the percentage of students passing in both the subjects?

Answer 1

P(fail in hindi)$=P\left(A\right)=35$%

P(fail in english)$=P\left(B\right)=45$%

P(fail in both)$=P(A\cap B)=20$%

$P(A\cup B)=P\left(A\right)+P\left(B\right)-P(A\cap B)=35+45-20$

$=60$% of students failed in atleast one.

No. of students who passed in both

$=100-60=40$%