The average money P and his seven friends have is ₹$450$. If P has ₹$120 more than the average money of his seven friends, how much money (in ₹) does P have?

Let the average money of P's seven friends be ₹$x$.Number of friends = $7$ Total money with the 7 friends = $7x$ According to the question, P has ₹$120$ more than the average of his seven friends:
$$\text{Money with P}=x+120$$
The total number of people including P is $1+7=8$ people. Their combined average is given as ₹$450$:
$$\text{Total Money}=8\times 450=3600$$
We also know that:
$$\text{Total Money}=\text{Total money with 7 friends}+\text{Money with P}$$
$$3600=7x+(x+120)$$
$$3600=8x+120$$
$$8x=3600-120$$
$$8x=3480$$
$$x=\frac{3480}{8}=435$$
Now, find the amount of money P has:
$$\text{Money with P}=x+120=435+120=555$$