Question

The average age of a teacher and three students is $20$ years. If all students are of equal age and the difference between the age of the teacher and that of a student is $20$ years, then the age of the teacher is-

• A. 25 years
• B. 30 years
• C. 35 years
• D. 45 years

Answer 1

Answer: (C)

Let the age of each student is $x$ years then the age of teacher is $(x+20)$ years
$\frac{(x+20)+3x}{4}=20\Rightarrow x=15$
Hence age of the teacher $=35$ years