Question

when a boy weighting 90 kgs left the class, the average weight of the remaining students increased by 400 g . what is the average weight of the remaining 199 students​

Answer 1

Hi friend,

I will give an example.... I think this will help you......

When a student weighing 45 kgs left a class, the average weight of the remaining 59 students increased by 200g. What is the average weight of the remaining 59 students?

SOLUTION:

Let, Average of 59 students = x

Let, Average of 59 students = xTotal of 59 students = 59x

Let, Average of 59 students = xTotal of 59 students = 59xTotal of 60 students = 59x+45

Let, Average of 59 students = xTotal of 59 students = 59xTotal of 60 students = 59x+45Average of 60 students = (59x+45)/60

Let, Average of 59 students = xTotal of 59 students = 59xTotal of 60 students = 59x+45Average of 60 students = (59x+45)/60now, x- 0.2 = (59x+45)/60

Let, Average of 59 students = xTotal of 59 students = 59xTotal of 60 students = 59x+45Average of 60 students = (59x+45)/60now, x- 0.2 = (59x+45)/6060x-12 = 59x+45

Let, Average of 59 students = xTotal of 59 students = 59xTotal of 60 students = 59x+45Average of 60 students = (59x+45)/60now, x- 0.2 = (59x+45)/6060x-12 = 59x+45i.e. x = 57

HOPE IT HELPS......