Instructions: Each of the following questions consists of a question followed by three statements I, II and III. You have to study the question and the statements and decide which of the statement (s) is/are necessary to answer the question.
What is the age of class teacher?
I. There are 11 students in the class.
II. The average age of students and the teacher is 14 years.
III. The average age of the teacher and students is 3 years more than that of students.
Let x be the average age of students
Let y be the teacher's age
$$\frac{11x + y}{12}$$ = 14
$$\frac{11x + y}{12}$$ = x + 3
Solving the above equations we get x = 11
y = 47
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