Multiple choice

Average age of A, B and C is 84 years. When D joined average becomes 80 years. A new person E who is 4 years older than D comes at place of A average age of B, C, D and E becomes 78 years. What is the age of A?

  1. 50 years

  2. 60 years

  3. 70 years

  4. 80 years
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A+B+C का औसत = 84, इसलिए A+B+C = 84×3 = 252। D के आने पर औसत 80 हो जाता है, तो A+B+C+D = 80×4 = 320। इससे D = 320−252 = 68। E, D से 4 वर्ष बड़ा है, तो E = 68+4 = 72। B,C,D,E का औसत 78 है, इसलिए B+C+68+72 = 78×4 = 312। इससे B+C = 312−140 = 172। A की आयु = 252−172 = 80 वर्ष। विकल्प D सही है।

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