Question

the everage weight of a class of 40 student is 40 kg.if the weight of the teacher be included,the everage weight increases by 500gm.the weight of the teacher is?

Answer 1

Average =(x1+x2----x40)/40

40=(x1+x2---x40)/40

40*40=(x1+x2--x40)

1600 =(x1+x2---x40)

Then, the sum of weight of students is 1600kg

If wieght of teacher will be included,

Average =40kg +500gram =40.5 kg

Average ={x1+x2---x40+ teacher's weight)/41

40.5 =(1600+teacher's weight) /41

40.5*41 =1600+ weight of teacher

1660.5 =1600 + wieght of teacher

1660.5 - 1600 = weight of teacher

660.5 kg =weight of teacher



I hope this will help you


-by ABHAY