Question

The average age of 24 students in a class is 15.5 years. The age of their teacher is 28 years more than the average of all twenty-five. What is the age of the teacher in years?

• A. 40 1/3
• B. 41 2/3
• C. 44 2/3
• D. 42 1/3

Answer 1

Answer:

C. 44 2/3

Solution: Given: The average age of 24 students in a class is 15.5 years. The age of their teacher is 28 years more than the average of all twenty-five. Formula Used: average = sum of observation/number of observation Calculation: Average age of 24 students in the class = 15.5 years ⇒ Total age of 24 students = 24 × 15.5 = 372 years Let age of teacher = x years and average age of all 25 = 372+x25 ⇒ x = 28 + 372+x25 ⇒ 25x - x = 700 + 372 ⇒ x = 1072/24=134/3 Thus, age of teacher = 44 2/3years