The average age of 24 students is 15.5 years. The age of the teacher is 24 years more than the average age of all the students and teacher. What is the age (in years) of the teacher?

40 41.4 42 40.5

40.5

Sum of 24 students = 24 x 15.5 = 372 Lets assume age of teacher be x ⇒ \(\frac{15.5 × 24 + x}{25}\) = x - 24 15.5 x 24 + x = 25x - 24 x 25 24x = 24 ( 25 + 15.5) x = 40.5 years