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In an examination, 19% students fail in Mathematics and 10% students fail in English. If 7% of all students fail in both subjects, then the number of students passed in both subjects is
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- 36 % of all students
- 64% of all students
- 71% of all students
- 78% of all students
Correct Option: D
n (A ∪ B)
= n(A) + n(B) – n (A ∩ B)
= 19 + 10 – 7 = 22%
i.e. 22% of students are unsuccessful in either one or two subjects.
∴ Percentage of successful students = 100 – 22 = 78%
Aliter : Using Rule 24,
a = 19%, b = 10%, c = 7%
Passed students in both the subjects
= 100 – (a + b – c)
= 100 – (19 + 10 – 7)
= 100 – 22 = 78%
