Answer with Step-by-step explanation:
Since we have given that
Cost of party per person = $20.
Let the number of friends be 'f'.
Let the cost of party be 'p'.
According to question, our equation becomes
p= 2f
So, if p = 100, then

if f = 10, then,

If p = 300 then,

If f = 20, then,

So, Table as follows:
Number of friends cost of party
50 100
10 20
150 300
20 40