Multiple choice

In a class there are 32 boys and 28 girls. The average age of the boys in the class is 14 years, and the average age of the girls in the class is 13 years. What is the average age of the whole class? (Rounded off to two digits after decimal)

  1. 13.50 years

  2. 13.53 years

  3. 12.51 years

  4. 13.42 years

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total age = (32 * 14) + (28 * 13) = 448 + 364 = 812. Total students = 32 + 28 = 60. Average = 812 / 60 = 13.5333.

AI explanation

Use the weighted average method to find the combined average age of the class. The total age of the 32 boys is 32 multiplied by 14, which is 448 years, and the total age of the 28 girls is 28 multiplied by 13, which is 364 years. The sum of these total ages is 812 years, and dividing this by the total class strength of 60 students gives an average age of 13.5333. Rounding this value to two decimal places results in 13.53 years.

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