1. Marco and his two younger sisters would like to purchase a silver charm bracelet for their mother’s birthday. They went to the mall and found what they were looking for at Store A. In Store A, the bracelet without charms costs $85 and each charm costs $15.

What would be the function of this? And What would be a reasonable domain for this function based on this scenario? Explain why this is a proper domain, and why this is the function.

Question

1.	Marco and his two younger sisters would like to purchase a silver charm bracelet for their mother’s birthday. They went to the mall and found what they were looking for at Store A. In Store A, the bracelet without charms costs $85 and each charm costs $15.

What would be the function of this? And What would be a reasonable domain for this function based on this scenario? Explain why this is a proper domain, and why this is the function.

imstuck · Answer

The function of this would be f(c) = 85 + 15x, which means in words, the function in terms of cost is equal to 85 dollars for the bracelet alone plus 15 dollars for each charm (which I designated as x.  X is the number of charms.)

anonymous · Answer

Where it asks what the function it, it should say function notation.

imstuck · Answer

See the main cost for the bracelet is 85, no matter if you put 0 charms on it or 100 charms on it.  What you spend on the bracelet depends upon how many charms you buy.  That is in function notation.  Unless you want me to use f(x) = 85 + 15x.  That look better?

imstuck · Answer

The first question, "What would be the function of this?" That answer is f(x) = 85 + 15x.

anonymous · Answer

Okay i had f(x)=15x+85

imstuck · Answer

Domain defines x values.  Just like the range defines y values.  Here, when they ask for a reasonable domain, they are asking for what is a reasonable x value.

imstuck · Answer

15x + 85 is the same as 85 + 15x.  As long as you have the x with the 15!

anonymous · Answer

so basically i just add 85 and 15x everytime to get the domain?

imstuck · Answer

I'M not sure how they want the domain noted.  If it is in an inequality statement, it would be reasonable for $$x \ge85$$I say that because even without the charms, the trio will spend at least $85.  I'm not sure how they want it noted.  Any ideas from any other problems like this in classs?

imstuck · Answer

In fact, use that for the domain.  The x is greater than or equal to 85.  That's a reasonable domain.

imstuck · Answer

This is a reasonable domain because, like I said, no matter if they buy any charms or not, they will spend at least $85.

imstuck · Answer

As for "Why is this the function?" The function is adding the base bracelet of $85 to each charm, x, that cost $15 apiece.

imstuck · Answer

That answers all the questions in your problem.  Do you understand?