Question

There is a total of 45 boys and girls in a choir.

Answer 1

Answer:

The mean age of all 45 boys and girls is 16.5years

Step-by-step explanation:

Since the mean age of the 18 boys is 16.2years,

∴ Sum of their ages = 18 × 16.2

                                 = 291.6years

The mean age of the 27 girls is 16.7years

∴ Sum of their ages = 27 × 16.7

                                 = 450.9years

∴ Mean age of all 45 boys and girls = $\frac{291.6 + 450.9}{45}$ years

                                                           = $\frac{742.5}{45}$ years

                                                           = 16.5 years

∴ The mean age of all 45 boys and girls is 16.5 years.

Answer 2

Answer:

16.5 year

Step-by-step explanation:

Using, mean = sum/no. *of observations

Here,

=> 16.2 = (sum of ages of boys)/18

=> 16.2 x 18 = sum of ages of boys

=> 291.6 = sum of ages of boys

Similarly, sum of ages of girls = 27 x 16.7 = 450.9

Mean(total) = (sumof agesof boys + girls)/45

Mean = (291.6 + 450.9)/45 = 16.5