The mean age of n men in a club is 50 years. Two men aged...
The mean age of n men in a club is 50 years. Two men aged 55 and 63 years left the club, and the mean age reduced by 1 year. Find the value of n.
30
20
18
14
Correct answer is B
Let the sum of the men's ages be f, so that
fn=50....(1)
Also, f−(55+63)n−2=50−1=49....(2)
From (1), f=50n
From (2), f−118=49(n−2)=49n−98
f=49n−98+118=49n+20
∴
50n - 49n = n = 20
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