Question

The total cost to buy pizzas from Mrs. miss holiday party can be found using the function C(x)=10+3.50x, where X is the number of pizza bought. She wants to order at least 5 pizzas but no more than 9 pizzas for class. Is this a continuous or discreet relationship?

What is the domain and what is the range of the situation?

Answer 1

We have the equation:

C(x) = 10 + 3.50*x

x represents the number of pizzas she buys, x only can take whole values, so we must have x ∈ Z

This means that this relation is discrete because there are only some values of x avaible, and thus there will be only some values of C(x) avaible.

She wants to buy at least 5 pizzas, and no more than 9, then the domain will be:

5 ≤ x ≤ 9

Or we could write the domain as:

{5, 6, 7, 8, 9}

This means that the possible costs will be:

C(5) = 10 + 3.50*5 = 27.50

C(6) = 10 + 3.50*6 = 31

C(7) = 10 + 3.50*7 = 34.5

C(8) = 10 + 3.50*8 = 38

C(9) = 10 + 3.50*9 = 41.50

Then the range is:

{27.50, 31, 34.5, 38, 41.50}