Question

The average weight of a group of persons increased from 48 kg to 51 kg, when two persons weighing 78 kg and 93 kg join the group. Find the initial number of members in the group.
1. 22
2. 23
3. 85
4. 46
5. None

Answer 1

Correct Answer - Option 2 : 23

Given:

Initial average of the group = 48

Increased average of the group = 51

Formula used:

Sum of weight = Average weight × Number of persons

Calculation:

Let the initial number of members in the group be x.

Initial total weight of all the members in the group = 48x

According to question,

⇒ 48x + 78 + 93 = 51 × (x + 2)

⇒ x = 23

∴ The initial number of members is 23