In a class of 70 students, 40 students have passed in Philosophy, 36 have passed in History, 10 students have failed in both the subjects. How many students have passed in Philosophy only?

Total students = 70

10 students have failed in both the subjects.

Passed students(either in any one subject or both the subjects) = 70-10 = 60    Eq.(i)

40 students have passed in Philosophy, 36 have passed in History.

So passed in Philosophy + passed in History = 40+36 = 76. But as per Eq.(i) 60 students passed. It means that 16 students passed in both the subjects.

Students passed in Philosophy only = 40-16 = 24