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.

Correct Answer: Option B

Explanation

Let the sum of the men’s ages be f, so that

(frac{f}{n} = 50 …. (1))

Also, (frac{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)

(therefore f = 50n = 49n + 20)

(50n – 49n = n = 20)