Question

In a class there are 50 students. The average weight of all the girls is 30 kg. The average weight of 30 of the boys is 40 kg. Which of the following can be a possible value of the average weight of the entire class(in kg)?

a) 31

b) 33

c) 35

d) 37

Answer 1

Answer:

b) 31

let total no. of boys be y and girls be 50-y respectively .

let total no. of boys be y and girls be 50-y respectively .( )/50- y = 30

let total no. of boys be y and girls be 50-y respectively .( )/50- y = 30 ( )/30 = 40

(1200+ 50 - y )/ 50 = _

(1200+ 50 - y )/ 50 = _y = 1550/50

(1200+ 50 - y )/ 50 = _y = 1550/50y = 31.

(1200+ 50 - y )/ 50 = _y = 1550/50y = 31. the average weight of entire class is 31 kg.