Question

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

Answer 1

Answer - 57 kg

Step-by-step explanation:

let intial average weight be X.

and intial weight of all students be Y.

if 1 student leaves class total no. of students becomes 59.

hence , total no. of students=59+1= 60

average= weight of all students/total no. of students

X=Y/ 60

Y=60X . . . (1)

average weight increases by 200g=0.2Kg

hence average weight = X+0.2

total no. of students decreases by 1

hence total no. of students= 59

weight of all students decreases by 45kg.

hence weight of all students =Y-45

now ,

average weight= weight of all students /total no. of students

X+0.2= Y-45/ 59

put Y=60X

X+0.2=60X-45/ 59

59X+11.8= 60X-45

11.8 +45= 60X-59X

X= 56.8

Average weight of remaining students =X+0.2=56.8+0.2= 57 Kg.