Question

If f(x) = 0.41x is a function that represents the cost to mail x number of letters, what is a reasonable domain for f?

A) All real numbers
B) All real numbers greater than 0
C) The set of all integers
D) The set of all whole numbers

Answer 1

The reasonable domain for the function f(x) = 0.41x, which represents the cost to mail x number of letters, is the set of all whole numbers (D).

Step-by-step explanation:

If f(x) = 0.41x represents the cost to mail x number of letters, then the reasonable domain for f would be the set of all whole numbers because you cannot mail a fraction of a letter or a negative number of letters. In other words, the number of letters x you can mail must be a whole number starting from zero (including zero since it's possible to mail no letters).

Therefore, the correct answer is D) The set of all whole numbers.