The average weight of a family of 8 members is 56 kg. The grandfather and the grandmother came to visit the family. Now, the average weight of 10 members of the family is 64 kg. Find the average weight (in kg) of the grandparents.

Correct option is C

Given:

Average weight of 8 members = 56 kg

Average weight of 10 members (including grandparents) = 64 kg

Formula Used:

Average =$$\frac{\text{ (Sum of weights) }}{\text{ (Number of members)}}$$​​

Solution:

Total weight of 8 members = 8 × 56 kg = 448 kg.

Total weight of 10 members = 10 × 64 kg = 640 kg.

Total weight of grandparents = 640 kg - 448 kg = 192 kg.​

Average weight of grandparents = $$\frac{192}{2}$$​= 96 kg.

Therefore, the average weight of the grandparents is 96 kg.