Question

The Average weight of a group of 5 students is 50 kg. One student leaves the group and average weight increases by 2.3 kg Find the weight
of the student who left the group.​

Answer 1

Given the average weight of 5 students is 50 kg

=> total weight of 5 students is 5×50 kg = 250kg

let the weight of student who left be x

ATQ

new average will be=

(250-x)/ 4 = 2.3 + 50

=> 250- x = 209.2 kg

=> x = 40.8kg

Ans: weight of student who left is 40.8kg

Answer 2

The weight of the student who left the group is 40.8 kg.

                                     

Given:

The average weight of 5 students is 50kg.

One student leaves the group and the average weight increases by 2.3 kg.

To Find:

We have to find the weight of the student who left the group.​

Solution:

Let us assume that the weight of the student who left the group is x kg.

The total weight of 5 students is (5×50)kg = 250 kg

Therefore, after one student leaves the group, the total weight of four students is (250-x)kg

So, the average weight of four students is  $\frac{250-x}{4}$ kg

According to the question,

                              $\frac{250-x}{4} = 50+2.3$

                           ⇒$250-x = 52.3 * 4$

                           ⇒$x=250-209.2$

                           ⇒$x=40.8$

 Hence, the weight of the student who left the group is 40.8 kg.                                      

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