Question

A store sells notebooks for $3 each and does not charge sales tax. If x represents the number of notebooks Adele buys and y represents the total cost of the notebooks she buys, which best describes the values of x and y? A,The value of x can be any real number, and y will be a real number.

b. The value of x can be any real number greater than or equal to 0, and y will be a real number greater than or equal to 0.
c. The value of x can be any integer, and y will be an integer.
d. The value of x can be any integer greater than or equal to 0, and y will be an integer greater than or equal to 0.

Answer 1

Only D is correct - if the notebooks cost 3.00 then A and B are eliminated since any real number can be a fraction or an irrational number. $3.00 is neither.
C is incorrect because any integer could allow for negative notebooks for example -4 notebooks = -$12. It is not possible to buy -4 notebooks.

Only D works since the price of a notebook is a positive integer (greater or = to ) and so is the price.

Answer 2

The value of x can be any integer greater than or equal to 0, and y will be an integer greater than or equal to 0.

Explanation:

Cost of 1 notebook = $3

x represents the number of notebooks

Since the number of notebooks cannot be negative .

So, x can be 0 or positive integer.

y represents the total cost of the notebooks .

Since Cost of 1 notebook is $3

So, Cost of notebooks will be in the multiples of 3.

So, y can be 0 or positive integer.

Thus Option D is correct.

The value of x can be any integer greater than or equal to 0, and y will be an integer greater than or equal to 0.