Bissoy.com
Doctors Medicines MCQs Q&A

The average weight of some persons in a group is 76 kg. If 15 persons with average weight 72 kg join the group or 5 persons with average weight 84 kg leave the group, the average weight of the persons in the group in both cases is the same. How many persons were there in the group, initially?

The average weight of some persons in a group is 76 kg. If 15 persons with average weight 72 kg join the group or 5 persons with average weight 84 kg leave the group, the average weight of the persons in the group in both cases is the same. How many persons were there in the group, initially? Correct Answer 45

Given:

The average weight of some persons in a group = 76 kg

Calculation:

Let, the total number of persons = x

15 persons with an average weight of 72 kg join the group

The average weight will reduce = /(x + 15) = 60/(x + 15)

5 persons with an average weight of 84 kg leave the group

The average weight will reduce = /(x - 5) = 40/(x - 5)

So, 60/(x + 15) = 40/(x - 5)

⇒ 3/(x + 15) = 2/(x - 5)

⇒ 3x - 15 = 2x + 30

⇒ 3x - 2x = 30 + 15

⇒ x = 45

∴ The total of 45 persons were there in the group.

Related Questions

The average weight of some persons in a group is 72 kg. When 5 persons with average weight 66.6 kg join and 13 persons with average weight 75 kg leave the group, the average weight of the persons in the group decreases by 1.65 kg. How many persons were there in the group initially?
The average weight of some boys in a group is 45 kg. If 10 boys with an average weight of 39 kg join the group or 10 boys with an average weight of 49 kg leave the group, then the average weight of boys in both cases is equal. How many boys were there in the group initially?
There are six persons namely A, B, C, D, E and F. They all take leave from office on any one day of the week starting from Monday to Saturday. Only one person takes leave on one day. C is the first person to take a leave. Three persons take leave between D and C. F takes leave just after D. E takes leave on Wednesday. B takes a leave after A. Who takes a leave on Thursday?
The average weight of some students in a group is 42 kg. If 8 students having average weight 44 kg leave the group and 3 students having average weight 48.25 kg join the group, the average weight of the new group is 50 g more than that of the original group. How many students were there in the group initially?
The average weight of some members of a club is 70 kg. If 15 members with an average weight of 60 kg join the club or 5 members with an average weight of 90 kg leave the club, then the average weight of members in both cases is equal. How many members were there in the club initially?
There are some children in a camp and their average weight is 40 kg. If 5 children with average weight 36 kg join the camp or if 5 children with average weight 43.2 kg leave the camp, the average weight of children in both cases is equal. How many children are there in the camp, initially?
The average weight of 30 persons of group A is 3 kg more than the average weight of 25 persons of group B. The average weight of 25 persons of group B is 2.5 kg more than the average weight of 20 persons of group C. If the total weight of 30 persons of group A is 1725 kg, then what will be the average weight of the persons of group A and group C taken together (in kg)?
There are some children in a camp and their average weight is 24 kg. If 5 children of average weight 18 kg join the camp or if 10 children of average weight \(24\dfrac{2}{4}\) kg leave the camp, the average weight in both cases remains equal. Initially, what is the number of children in the camp?
If 10 employees in an organization having an average weight of 73 kg leave and 5 employees having an average weight of 70 kg join, the average weight of the employees in the organization decreases by 0.4 kg. The average weight of all employees in the organization initially is 70 kg. If the number of employees initially in the organization is n, which of the following is/are correct? I. 73 employees are left II. n is a multiple of 16 III. 70 < n < 80
There are seven persons - A, B, C, D, E, F and G. They have different weights. The weight of second heaviest person is 185 kg and the weight of second lightest person is 85 kg. Sum of weight of C and D is 290 kg. Only Three persons have more weight than D. E is heavier than both F and G but F is not lightest. The weight of A is 250 kg. Sum of weight of F and G is 135 kg. B is heavier than both C and D but C is not lightest. The weight of D is 140 kg. The weight of E is obtained from removing weight of C from weight of A. Who is the Fourth lightest person?