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 is B

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