The mean age of R men in a club is 50 years, Two men aged 55 and 63, left the club and the mean age reduced by 1 year. Find the value of R
A. 18 B. 20 C. 22 D. 28
Correct Answer: B
Explanation
mean age = \(\frac{\text{sum of ages}}{\text{no. of men}}\) 50 = \9\frac{sum}{R}\) sum = 50R.....(1) Sum of ages of the men that left = 55 + 63 = 188 remaining sum = 50R - 118 remaining no. of men = R - 2 now mean age = 50 - 1 = 49 years 49 = \(\frac{50R - 118}{R - 2}\) 49(R - 2) = 50R - 118 49R - 50R = -188 - 98 -R = -20 R = 20