The average marks of 30 students in a test is 40. The average of those who passed is 45 and the average of those who failed is 30. How many students passed?

A. 22

B. 20

C. 10

D. 18

Doubtly AI Asked 27 Oct 2026 AI-generated · not yet verified ssc cgl Save WhatsApp Report

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Answer: B. 20

Answer: (B) 20

Shortcut (alligation): passed : failed = (40 − 30) : (45 − 40) = 10 : 5 = 2 : 1. Passed = \(\frac{2}{3} \times 30 = 20\).

Plain: 45p + 30(30 − p) = 1200, so 15p = 300 and p = 20.

Doubtly AI · 27 Oct 2026 AI-generated · not yet verified Report

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