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

The objective is to determine the revised average weight following the departure of one student.

1. Foundational Principles:

- Average Weight: The sum of all weights divided by the count of individuals.
- Revised Average: Calculate the updated total weight after an individual's removal and divide by the reduced count of individuals.

2. Provided Data:

- Initial student count = 10
- Initial average weight = 50 kg
- Weight of departing student = 60 kg

3. Computation of the Revised Average:

Initial total weight = \( 10 \times 50 = 500 \) kg
Revised total weight = \( 500 - 60 = 440 \) kg
Revised student count = \( 10 - 1 = 9 \)
Revised average = \( \frac{440}{9} \approx 48.89 \) kg

Conclusion:

The new average weight is approximately 49 kg.