Question

Please expain this question..

Answer 1

there are a certain no. of students in a class

the weight of each student is added nd the sum is divided by the total no. of students

then 12 students entered whose sum of weight was divided by 12

then when the total no. of students weight as well as the 12 students weight was added nd divided by total no. of students we get the avg weight which is 2.5 more than earlier so now find the total no. of students

Answer 2

Let the no. of students be x.

Then, total weight = mean weight × X

= 37.5X

New weight = Original weight + 12×50

=> 40(x+12) = 37.5X + 6000

=> 40x + 4800 = 37.5x +6000

=> 40x - 37.5x = 6000 - 4800

=> 2.5x = 1200

=> x = 1200/2.5

= 12000/25

= 480.

There were 480 students in the class at beginning..

hope it helps...