Question

In the above example, if the average weight is decreased by 1Kg , then find the weight of new person. 

Answer 1

Let the average weight of a group = x
∴ Total weight of 30 persons =30x 

Let the weight of new person = y
        ∴From the quetions, 

30x - 40 + y = 30(x - 1)

⇒ 30x - 40 + y = 30x - 30

⇒ y = 40-30 

∴ y = 10 kg

Hence, The age of new person is 10kg