Inan examination, 55% candidates passed in English, 35% candidates passed In mathematics and 20% candidates passed in both the subjects. If the total number of failed candidates in both the subjects is 1200, then find how many candidates took the exam.

Number of candidates failed in both subjects = 1200
% candidates passed in English = 55%
% candidates passed in Mathematics = 35%
% candidates passed in both English and Mathematics = 20%
Formula Used:
P(A or B) = P(A) + P(B) - P(A and B)
A represents passing in English and B represents passing in Mathematics.
Solution:
the percentage of students who passed in at least one subject = 55% + 35% - 20% = 70%.
If 70% passed in at least one subject, then 100% - 70%
= 30% failed in both subjects.
30% of the total students = 1200
0.30 $$\times$$​ Total students = 1200
Total students = $$\frac{1200} { 0.30}$$​= 4000