The average age of a class of 15 students is 10 years. If the age of the teacher be included, then the average increased by 1year. Find the age of the teacher?  Select.
A) 22  B) 23  C) 26  D) 29  E) 31

Rationale: "total age of 15 persons = 15 * 10 = 150 years average age of 16 persons = 11 years total age of 16 persons = 16 * 11 = 176 years age of the teacher = 176 - 150 = 26 years answer is c"
Answer: C