Question:
The average age of a class of 39 students is 15 years. If the age of the teacher be included, then the average increases by 3 months. Find the age of the teacher.
The average age of a class of 39 students is 15 years. If the age of the teacher be included, then the average increases by 3 months. Find the age of the teacher.
Updated On: May 25, 2025
- 20
- 25
- 35
- 30
Hide Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Step 1: Calculate the total age of the students
\[ 39 \times 15 = 585 \text{ years} \]
Step 2: Calculate the total age after including the teacher
After including the teacher, the total number of people becomes 40, and the new average age is:
\[ 15 + \frac{3}{12} = 15.25 \text{ years} \]
The total age of the 40 persons is:
\[ 40 \times 15.25 = 610 \text{ years} \]
Step 3: Find the teacher's age
\[ 610 - 585 = 25 \]
Thus, the teacher’s age is 25 years.
Was this answer helpful?
1
0
Top Questions on Average
- A batch of 36 school children goes for an excursion trip to Nainital. When one 10-year-old child is replaced with another child, the average age of the children in the batch increases by \( 2\frac{1}{2} \) months. What is the age of the new child?
What is the sum of ages of Murali and Murugan?
Statements: I. Murali is 5 years older than Murugan.
Statements: II. The average of their ages is 25- If \( a \) and \( b \) are non-negative real numbers such that \( a + 2b = 6 \), then the average of the maximum and minimum possible values of \( (a + b) \) is
- If the average income of seven families is Rs. 4200 and a family with an income of Rs. 1000 joins them, then the average income of all eight families is (in Rs)
- The average weight of 10 students is 50 kg. If one student weighing 60 kg leaves the group, what is the new average weight?
View More Questions
Questions Asked in ATMA exam
- It XY = 5:7, XZ 3:8 and W:Y4:9 then what is X: W?
- ATMA - 2021
- Ratio and Proportion
- What is the next number in the series given below?
\(10, 11, 13, 17, 25, 32, 37, 47, ?\)- ATMA - 2021
- Series
- Investment of ₹ 4,000 at \(R\%\) per annum compounded annually becomes 16,000 in 8 years. If 2,000 is invested at \(R\%\) per annum compounded annually, then in how many years will the investment become 16,000?
- ATMA - 2021
- Basic Algebra
- Choose the correct option to complete the sentence:
This is a birthday gift___my brother.- ATMA - 2021
- Fill in the Blanks
- Six books are placed from left to right on a shelf. History book is neither on extreme left nor on extreme right. English book is to the immediate left of Science book. Geography book has three books to its right side. Between Science and Sociology books, there are exactly two books. Remaining one book is of Arts. How many books are there to the right of History book?
- ATMA - 2021
- Reasoning
View More Questions