In a class 80% have passed english,70% passed Hindi 10% did not passed either.…
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In a class 80% have passed english,70% passed Hindi 10% did not passed either. If 144 students passed both. What is the total strength of the class.
- A.
240
- B.
120
- C.
360
- D.
480
Attempted by 56 students.
Show answer & explanation
Correct answer: A
Key idea: use inclusion–exclusion and the fact that 10% did not pass either subject.
Step-by-step:
Students who passed at least one subject = 100% - 10% = 90%.
By inclusion–exclusion: percentage passed English + percentage passed Hindi - percentage passed both = percentage passed at least one. So 80% + 70% - both% = 90%.
Solve for percentage who passed both: both% = 80% + 70% - 90% = 60%.
Given that 60% of the class equals 144 students, total students = 144 ÷ 0.60 = 240.
Answer: Total number of students = 240