Question

The average weight of 10 students is 50 kg. If one student weighing 60 kg leaves the group, what is the new average weight?

• A. 48 kg
• B. 49 kg
• C. 47 kg
• D. 50 kg

Hint:

For average problems, calculate the total sum (average $\times$ number of items). Adjust the sum when an item is removed, then divide by the new number of items. Alternatively, use the formula: New average = Old average - $\frac{\text{Removed value} - \text{Old average}}{\text{New count}}$. Check if the problem expects rounding based on options.

Answer 1

The Correct Option is B

To solve the problem, we need to find the new average weight after one student leaves the group.

1. Understanding the Concepts:

- Average Weight: Total weight divided by the number of students.
- New Average: Calculate the new total weight after one student leaves and divide by the new number of students.

2. Given Values:

- Number of students = 10
- Average weight = 50 kg
- Weight of the student who leaves = 60 kg

3. Calculating the New Average:

Total weight = \( 10 \times 50 = 500 \) kg
New total weight = \( 500 - 60 = 440 \) kg
New number of students = \( 10 - 1 = 9 \)
New average = \( \frac{440}{9} \approx 48.89 \) kg

Final Answer:

The new average weight is approximately 49 kg.