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)?

The correct option is 58.

Let us break down the problem step-by-step to find P's weight.

Step 1: Understand the average weight of P and his three friends.
We are given that the average weight of P and his three friends (a total of 4 people) is 55 kg.
Let $P$ represent P's weight in kg, and let $F$ represent the average weight of his three friends in kg.
Since there are 3 friends, the sum of the weights of his three friends is:
$3\times F$

The sum of the weights of all 4 people (P and his three friends) is:
$P+3F$

Since their average weight is 55 kg, we can write the equation for the average:
$\frac{P+3F}{4}=55$

Multiplying both sides by 4 gives the sum of their weights:
$P+3F=220$ (Equation 1)

Step 2: Relate P's weight to the average weight of his three friends.
We are told that P's weight is 4 kg more than the average weight of his three friends ($F$):
$P=F+4$

We can rewrite this equation to express $F$ in terms of $P$:
$F=P-4$ (Equation 2)

Step 3: Substitute Equation 2 into Equation 1 to solve for P.
Substitute $F=P-4$ into $P+3F=220$:
$P+3(P-4)=220$

Expand the equation:
$P+3P-12=220$

Combine like terms:
$4P-12=220$

Add 12 to both sides of the equation:
$4P=232$

Divide by 4 to find P's weight:
$P=\frac{232}{4}$

$P=58$

Thus, P's weight is 58 kg.