The average age of 42 students in a group is 16 years. When teacherâ€™s age is included to it, the average increases by one. What is the teacherâ€™s age in years?  Choices:
A) 31
B) 56
C) 41
D) 59
E) None
Sol.   Age of the teacher = ( 43 Ã— 17 â€“ 42 Ã— 16 ) years = 59 years.   Answer 59
<result>D</result>
The average age of 42 students in a group is 16 years. When teacherâ€™s age is included to it, the average increases by one. What is the teacherâ€™s age in years?