The average age of 20 students in a class is 5years. If teacher's age is also included then average increases 1year then find the teacher's age?
Select:
A) 28	B) 24	C) 20	D) 22	E) 18

Rationale: "total age of 50 students = 20 * 5 = 100 total age of 51 persons = 20 * 6 = 120 age of teacher = 120 - 100 = 20 years answer is c"
Answer: C