Question

Mean weight of students in a class is 48 kg. If men weight of girl students is 40 kg. and that of
is 60 kg. Find (a) % age of boys and girls (b) If there are total of 75 students, find number of each​

Answer 1

answers-

(a)

% of girls = 12/20×100 = 60%

% of boys = 8/20×100 = 40%

(b)

Boys=  30

 Girls =  45

Step-by-step explanation:

Given data as per question

Mean weight of students in class = 48 kg

Mean weight of girls = 40 kg

Mean weight of boys = 60 kg

Calculations

(a)

Let no. of girls =x

No. of boys = y

Let the total weight of the students be z.

Mean of the weight of the students will be  

z/(x+y) = 48

z = 48(x+y)  

z = 48x+48y   -----(1)

Total weight of girls = 40 x

Total weight of boys = 60 y

Total weight of boys and girls = 40  x + 60 y      --(2)

Equating equation 1 and 2 we get  

48x+48y   = 40  x + 60 y      

48x-40x =60y – 48 y

8 x = 12 y

x/y = 12/8

% of girls = 12/20×100 = 60%

% of boys = 8/20×100 = 40%

(b)

Total no. of students = 75

Boys= 75×0.40 = 30

 Girls = 75×0.60 = 45