Question

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. Use function notation that models the total price of the bracelet and how that price is based on the number of charms. Explain the reasoning behind your equation. What would be a reasonable domain for this function based on this scenario? Explain why this is a proper domain. If Marco and his sisters have saved $250, make a graph to show all of the charms they could purchase with a bracelet if they had saved between $85 and $250. Marco found five charms that he likes. Using your function, determine the cost of the bracelet he would make. As they walked down the hall of the mall, Marco saw this sales flyer for Store B on a bench.

Answer 1

Given:
Cost of bracelet without charm - $85
cost of each charm - $15

Function notation: f(x) = 15x + 85

The price of the bracelet depends on the number of charms they will buy. x represents the number of charms they will buy. 

The reasonable domain for this function is at least 1. They must buy at least 1 charm because they intend to buy their mom a silver charm bracelet.

If their budget is 250

250 = 15x + 85
250 - 85 = 15x
165 = 15x
165/15 = x
 11 = x

They can buy at most 11 charms without going beyond their budget.