The average age of 28 students in a group is 11 years. When teacher’s age is included to it, the average increases by one. What is the teacher’s age in years? Pick.
A) 36
B) 38
C) 40
D) cannot be determined
E) None of these
Age of the teacher = (29 × 12 – 28 × 11) years   = 40 years.   Answer 40
<result>C</result>
The average age of 28 students in a group is 11 years. When teacher’s age is included to it, the average increases by one. What is the teacher’s age in years?