Problem:
In an Examination,35% fail in maths and 25% fail in English.If 10% fail in both the subjects.Then how much % pass in both?
Solution:
I applied the formula:
P(M)=Percentage of people fail in maths=35%.
P(E)=Percentage of people fail in english=25%.
P(M U E)=Percentage of people fail in in maths or english. P(M U E)=P(M)+P(E)-P(M intersection E)
35%+25%-10%=50% fail in either of the subjects.
But I am unable to calculate how to calc pass % in both subjects?
Can anyone guide me how to solve this problem?
De Morgan's law is $$\mathrm{not}(A\ \mathrm{or}\ B)=(\mathrm{not}\ A)\ \mathrm{and}\ (\mathrm{not}\ B)$$ So if they don't (fail math or fail English) then...