In a hotel, there are 10 staff members. Their average weight is 50 kg. When one of the staff members leaves the hotel, the average weight becomes 49 kg. If one new staff member join the average weight becomes 52 kg. Find the difference between the weight of the staff member who left the hotel and who join the hotel.

Question

Question

This question was previously asked in

SBI Clerk Prelims Memory Based Paper (Held On: 5 January 2024 Shift 1)

Answer 1

Given:

Total number of staff members = 10

Average weight = 50 kg

Reduced average weight = 49 kg

Increased average weight = 52 kg

Formula used:

Average = \(Sum\: of \:weight \:of \:all \:the \:staff \: members \over Total\: no.\: of \:staff \: members \)

Let the weight of that one staff member who left be x,

and addition of weight of other staff be y.

Calculation:

The total weight of all the staff members in the hotel before one of them left is:

10 staff members × 50 kg/person = 500 kg

When one staff member leaves, the total weight of the remaining 9 staff members is:

9 staff members × 49 = 441 kg

Weight of leaving member = 500 - 441 = 59 kg

When one staff member joins, the total weight of the 10 staff members is:

10 × 52 = 520 kg

Weight of new joining staff member = 520 - 441 = 79 kg

Difference between the weight of the staff member who left the hotel and who join the hotel = 79 - 59 = 20 kg