Question

41. The average weight of boys in a class is 52 kg and that of girls is 47 kg. If the
average weight of all the students of the class is 49.6 kg and the number of boys
is 3 more than the number of girls, what is the total number of students in the
class?
1) 75 2) 72

5) 30
4) 50
2) 40
​

Answer 1

The answer is 72 of your question

Answer 2

Step-by-step explanation:

Let the no. of boys = x

sum of the weight of boys = 52 × x

= 52x

Let the no. of girls = y

sum of the weight of girls = 47 × y

= 47y

sum of all students = 52x + 47y

total no. of students = x + y

(52x + 47y)/(x+y) = 49.6

& no. of boys = 3 + no. of girls

x = 3 + y

(52x + 47y)/(x+y) = 49.6

(52x + 47y) = 49.6(x + y)

52x + 47y = 49.6x + 49.6y

52x - 49.6x = 49.6y - 47y

2.4x = 2.6y

(putting the value of x = 3 + y)

2.4(3 + y) = 2.6y

7.2 + 2.4y = 2.6y

2.4y - 2.6y = -7.2

-0.2y = -7.2

y = (-7.2)/(-0.2)

y = 72/2

y = 36

x = 3 + y

x = 3 + 36

x = 39

total no. of the students = x + y

= 36 + 39

= 75 (Answer)