Question

51. The average age of 30 students of a class is 12 years. The average age of a group of 5 of the students is 10 years and that of another group of 5 of them is 14 years. What is the average age of the remaining students?
(1) 8 years (2) 10 years
(3) 12 years (4) 14 years
(5) None of these​

Answer 1

Answer:12 YRS

Step-by-step explanation:

The total age of the 30 students = 30*12 = 360 years.

The total of the first 5 students = 5*10 = 50 years.

The total of the next 5 students = 5*14 = 70 years.

So the total of the remaining 30–5–5 or 20 students = 360–50–70 = 240 years.

Or the average age of the remaining 20 students = 240/20 = 12 years.