Question

There are 30 boys and 60 girls in a class . If the average age oF boys is 12 yrs and the average of girls are 10 find the average of the whole class ?

• A. 10.66
• B. 12.05
• C. 12.22
• D. 10.32

Answer 1

Answer:

A. 10.66

• Calculate the Total Age of Boys: The number of boys is 30, and their average age is 12 years.Total Age of Boys = Number of Boys × Average Age of Boys = 30 × 12 = 360 years.

• Calculate the Total Age of Girls: The number of girls is 60, and their average age is 10 years.Total Age of Girls = Number of Girls × Average Age of Girls = 60 × 10 = 600 years.

• Calculate the Total Age of the Whole Class: Add the total ages of boys and girls to get the sum of ages for all students.Total Age of Class = Total Age of Boys + Total Age of Girls = 360 + 600 = 960 years.

• Calculate the Total Number of Students in the Class: Sum the number of boys and girls to find the total population for the average.Total Number of Students = Number of Boys + Number of Girls = 30 + 60 = 90 students.

• Calculate the Average Age of the Whole Class: Divide the total age of the class by the total number of students.Average Age of Class = Total Age of Class / Total Number of Students = 960 / 90 = 96 / 9 = 32 / 3 ≈ 10.666... years. This is often rounded to 10.67 or truncated to 10.66 depending on the exam options.