The average age of 29 students in a group is 15 years. when teacher's age is included to it, the average increases by one.What is the teacher's age in years?  Pick one.
A) 31	B) 36	C) 29	D) 53	E) 57

Rationale: age of the teacher = ( 29 * 16 - 29 * 15 ) = 29 years . answer : c
Answer: C