B. 16
Feedback The average age of a group of 10 students is 10.
Therefore, the sum of the ages of all 10 of them = 10 * 10 = 100
When two students joins the group, the average increase by 1.
New Average = 11
Now there are 12 students
Therefore, sum of all the ages of 12 students = 132
Therefore, the sum of the ages of two students who joined = 132 - 100 = 32
And the average age of these two students = 16