### The average age of 24 boys and their teacher is 15 years. When the teacher’s age is excluded, the average age decreases by 1 year. The age of the teacher is :

**A.** 38 years

**B.** 39 years

**C.** 40 years

**D.** 41 years

## Show Answer

###
Answer-B

Solution-

__Solution(By Apex Team)__

The total age of 24 boys and teacher is
$\begin{array}{l}\text{= 25 × 15}\\
\text{= 375 years}\end{array}$
Let the teacher’s age = x years
According to the question,
$\begin{array}{l}\text{25 × 15 = 24 × 14 + x}\\
\text{375 = 336 + x}\\
\text{x = 39 years}\end{array}$