The average weight of P and his three friends is 55 kg. If P is 4 kg more than the average weight of his three friends, What is P's weight (in kg) ?

58

Let's assume avge. weight of P's friends is x

weight of P will be x + 4

and Total weight of all P and his friends will  be = (x + 4) + 3x = 4 x 55

⇒ 4x= 4 x 55 - 4 = 4 x 54

x=54

So weight of P = 54 + 4 = 58 Kg