Answer:
The price of the cake proportional to the number of people.
Step-by-step explanation:
Let N be the number of people and P be the price of the cake.
If P is proportional to the N, then
P = kN, where k is constant of proportionality.
k = P/N.
If the price of the cake is truly proportional to the number of people then k should be the same for all values of P and N.
When P = $20, $32 and $48, N = 5, 8, and 12 respectively.
k = 20/5 = 32/8 = 48/12
k = 4.
Hence, the price of the cake proportional to the number of people.