Que: A fitness club has 40 male and 10 female members. The average (arithmetic mean) age of all of the members

Solution: We have 40 males and 10 females. Hence, total members are: 40 + 10 = 50

Let the average age, in years, of the female members be x, then we get

=> \(\frac{40\ \cdot22\ +\ 10\ \cdot\ x}{40\ +\ 10}\ =\ 24\)

=> 40 * 22 + 10x = 24 * 50

=> 880 + 10x = 1,200

10x=1200 – 880 = 320 which means that the sum of the ages of 10 female members is 320

Also, we get 10x = 320, x = \(\frac{320}{10}=32\) , which means that the average age of these 10 female members is = 32.

C is the correct answer.

Answer C