Question

Average weight of A,B,C is 2 kg.
If D is added, Average weight increases by 1 kg.
that means, Average weight of A,B,C,D is 3 kg.
find the actual weight of D.

Options are :-
3 kg
4 kg
5 kg
6 kg

Fast and Right answer will be marked as BRAINIEST.

Answer 1

$average = \frac{sum}{total \: no.}$
Thus
$average \: of \: a \: b \: and \: c = \frac{their \: sum}{3}$
$2 = \frac{their \: sum}{3}$
$their \: sum \: = 6$
When D is added average increases by 1 kg i.e 3kg

Similarly
$sum \: when \: d \: is \: added = 12$
D's weight = New average - old average
=12-6
= 6kg

Thus,

D has a weight of 6 kg i.e the last option

Answer 2

A+B+C /3 = 2

I.e A+B+C=6...(1)

Then ,, D is added and

A+B+C+D /4=3

I.e A+B+C+D = 12....(2)

now substrate eq.1 from eq 2
you will get D= 6

that actual weight of D .