Question

Q1 If the mean weight of 40 students of a class is 53 kg, then their total weight is:​

Answer 1

Answer:

Let x be the number of boys, then the number of girls will be (60−x).

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

The mean weight of girls is 30 kg, then the total weight of girls will be 30(60−x)=1800−30x.

The mean weight of 60 students is 40 kg, so

totalno.ofstudents

weightofgirls+weightofboys

=40

60

1800−30x+50x

=40

x=

20

600

x=30

So, the number of boys is 30 and the number of girls is (60−30)=30.

Answer 2

Answer:

2120 kg.

Step-by-step explanation:

$weight \: of \: 1 \: student \: = 53 \: kg.$

$weight \: of \: 40 \: students \: = 53 \times 40$

$weight \: of \: 40 \: students \: = \: 2120 \: kg.$