Question

The average weight of 5 quantities is 10 kg and the average weight of 3 of them is 9 kg. What is the average weight of the remaining 2?

• A. 6 kg
• B. 6.5 kg
• C. 7 kg
• D. 6.25 kg

Hint:

When calculating the average weight of remaining items, subtract the known quantities' total from the overall total and divide by the remaining items.

Answer 1

The Correct Option is B

To solve the problem, we will use the formula for the average, which is given by the total weight divided by the number of quantities. First, find the total weight of all 5 quantities and then the total weight of the 3 quantities. Subtract to find the total weight of the remaining 2 quantities and then calculate their average.

1. Total weight of all 5 quantities:
   The average weight of 5 quantities is 10 kg.
   Total weight = Average × Number of quantities = 10 kg × 5 = 50 kg.
2. Total weight of the 3 quantities:
   The average weight of 3 of them is 9 kg.
   Total weight = Average × Number of quantities = 9 kg × 3 = 27 kg.
3. Total weight of the remaining 2 quantities:
   Total weight of 2 quantities = Total weight of 5 quantities - Total weight of 3 quantities = 50 kg - 27 kg = 23 kg.
4. Average weight of the remaining 2 quantities:
   Average = Total weight of 2 quantities / Number of quantities = 23 kg / 2 = 11.5 kg.

Hence, the average weight of the remaining 2 quantities is 11.5 kg.