I really only need confirmation here... I’m stuck on which of the two answers (A or C) it is. Hector’s service club is raising money by wrapping presents in the mall. The function f(x) = 3x describes the amount of money, in dollars, the club will earn for wrapping x presents. They only have enough wrapping paper to wrap 1000 presents.

Describe the domain of the function.

A. All real numbers such that 1000 ≥ x ≥ 0 (I flipped the problem because I couldn’t find the sign. Really it would be 0 ≥ x ≥ 1000 with the signs facing the other way)

B. All real numbers

C. All whole numbers such that 1000 ≥ x ≥ 0 (I flipped the problem because I couldn’t find the sign. Really it would be 0 ≥ x ≥ 1000 with the signs facing the other way)

D. All whole numbers

The answer is C

Step-by-step explanation:

The digits n, n+1 and n+2 implies that the special numbers are consecutive i.e. they follow one another. The count of special numbers less than 1000 is 17.

Given that:

First, calculate the LCM of 4, 5 and 6.

So, the LCM is:

This means that the special digit occurs after every other 60 digits (i.e. the difference between a special digit and another is 60)

To calculate the count of special digits, we make use of arithmetic progression formula

Where

--- the last term

--- the first special digit

--- the common difference as explained above

So, we have:

Collect like terms

Divide both sides by 60

Add 1 to both sides

Rewrite as:

Remove the decimal part (do not approximate)

Hence, the special numbers are 17 in total (that are less than 1000).

Read more about arithmetic progression at: