Question

$\huge{\mathfrak{\blue{QUESTION}}}$

THE MEAN WEIGHT OF 60 STUDENTS IN A CLASS IS 40KG.THE MEAN WEIGHT OF BOYS IS 50 KG WHILE THAT OF GIRLS IS 30 KG . FIND THE NUMBER OF BOYS AND GIRLS IN CLASS​

Answer 1

Answєr :

Let x be the number of boys, then the number of girls will be [60 - x]

The mean weight of the boys is 50 kg, then the total weight of the boys will be 50x

The mean weight of the girls is 30 kg, then the total weight of the girls will be 30[60 - x] = 1800 - 30 x

The mean weight of the students is 40 kg, so

Weight of the girls + Weight of the boys

____________________________ = 40

Total number of students

1800 - 30x + 50x

______________ = 40

60

x = 600

___

20

x = 30

So the number of boys is 30 and number of girls is [60 - 30] = 30

Hopє this hєlps you !

Answer 2

Answєr :

Let x be the number of boys, then the number of girls will be [60 - x]

The mean weight of the boys is 50 kg, then the total weight of the boys will be 50x

The mean weight of the girls is 30 kg, then the total weight of the girls will be 30[60 - x] = 1800 - 30 x

The mean weight of the students is 40 kg, so

Weight of the girls + Weight of the boys

____________________________ = 40

Total number of students

1800 - 30x + 50x

______________ = 40

60

x = 600

___

20

x = 30

So the number of boys is 30 and number of girls is [60 - 30] = 30

Hopє this hєlps you !