600 students took the test on Physics and chemistry. 35% students failed in Physics and 45% students failed in chemistry and 40% of those who passed in chemistry also passed in Physics, then how many students failed in both :

Explanation:-

Result	Physics	Chemistry
Failed	35%	45%
Passed	65%	55%

Now, 55% of 600 passed in Chemistry = (55 X 600) / 100 = 330 From question, 40% of those who passed in Chemistry(330 Students) also passed in physics => (40 X 330) / 100 = 132 ,
so, 132 students passed in both
Therefore % who passed in both = (132 X 100 ) / 600 = 22%
Passed in both subject = 22% of total students
% of students who passed in either Physics or Chemistry or both,
= (65 +55) -22 = 98%
Thus, percentage of students who failed in both subjects,
= 2%
Number of students who failed = 2% of 600 = 12.