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.

Answer 1

A. 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.
B. What would be a reasonable domain for this function based on this scenario? Explain why this is a proper domain.
C. 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.
D. Marco found five charms that he likes. Using your function, determine the cost of the bracelet he would make.
E. As they walked down the hall of the mall, Marco saw this sales flyer for Store B on a bench.

Answer 2

@misty1212

Answer 3

Marco is wondering from which store he should buy the items so that he spends the least amount of money. Which store should Marco use if he wanted the five charms and silver bracelet all together? What advice can you tell Marco to help him shop wisely depending on the number of charms he wants to buy? Justify how you reasoned your answers.

Answer 4

HI!

Answer 5

Haiii :D

Answer 6

if you buy say \(x\) charms then you have to pay \(\$15\) each for a total cost of
\[C(x)=85+15x\]

Answer 7

thats A?

Answer 8

lol yeah that is A

Answer 9

the domain would be the number of charms you buy
you can buy 0, 1, 2, 3, 4,5, ... charms so i would say whole number from zero to say 20 or so?

Answer 10

and that is B

Answer 11

for b just say that it would be a whole number from zero to 20 or more?

Answer 12

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.

i don't know how to make a graph, but the most charms they could buy you would solve
\[85+15x=250\] and get
\[15x=165\\
x=11\]so between zero charms and eleven charms

Answer 13

you decide how many charms you can fit on one bracelet for the domain

Answer 14

i just made up the 20

Answer 15

Marco found five charms that he likes. Using your function, determine the cost of the bracelet he would make.\[C(5)=85+15\times 5\] compute that number

Answer 16

how would i make this graph?

Answer 17

oh oh u said u dont know xd

Answer 18

no idea
i guess you could graph the line
\[y=85+15x\]
http://www.wolframalpha.com/input/?i=y%3D85%2B15x

Answer 19

x=11? for the first

Answer 20

omg im so behind xd ur telling me it and I'm just blindly answering like u never told me xd

Answer 21

but don't make it look like that because it can't be negative
make it look like this

Answer 22

go slow, read what i wrote, it is all there
be careful

Answer 23

i have answered A, B, C, and D
after you read them let me know, make sure you understand them, then we can do E if you like

Answer 24

oh so dont make it look like that graph?

Answer 25

no because the domain is not all real numbers, they have to be positive.
only what it looks like in the first quadrant
i can't seem to use the draw tool to show you

Answer 26

nope, not working

Answer 27

would d be 20?

Answer 28

ok back up to D I'm still confused on that which thing did u write that is D?

Answer 29

D i wrote here
Marco found five charms that he likes. Using your function, determine the cost of the bracelet he would make.
\[C(5)=85+15×5\]
compute that number

Answer 30

oh and i got 20 for c ?

Answer 31

\[85+15\times 5\]

Answer 32

160 :D

Answer 33

ok but C is not 20
i wrote it above, question and answer
take a look

Answer 34

15x=165
x= 11 that one?

Answer 35

yes that one

Answer 36

oh ur saying they can buy 11 charms @misty1212

Answer 37

yes zero to 11 because that is what you get if you solve
\[85+15x=250\]for \(x\)

Answer 38

so ok 11 charms i would make the graph starting at 85 on the y axis and 0-11 on the x axis and plot dots on each like 0-11 or would i use a graph?

Answer 39

sure why not?

Answer 40

https://www.desmos.com/calculator if i type in the equation do i get the graph?

Answer 41

@misty1212

Answer 42

this is going to give you a lousy picture
the scale is wrong
and you only want the graph in quadrant i

Answer 43

oh ok let me make a pic and see if its right

Answer 44

k

Answer 45

no this won't work i was going to do a line graph but no @misty1212

Answer 46

yeah i know i tried too
just move on

Answer 47

So d is 160 ryt? @misty1212

Answer 48

YUP

Answer 49

:D yay ok so lets move on to E

Answer 50

the first one we had the equation
\[85+15x\]
the second one would be \[100+12x\]and you want to know which one is cheaper
it will depend on the number of charms you buy
if you buy a lot the second one will be
if you buy fewer, the first one will be cheaper
to find the number at which it changes set them equal and solve for x

Answer 51

how do i set them as equal do i put it like 85+15x 100+15x ?

Answer 52

\[85+15x=100+12x\] yes

Answer 53

ok so I'm still very confused

Answer 54

like Which store should Marco use if he wanted the five charms and silver bracelet all together? What advice can you tell Marco to help him shop wisely depending on the number of charms he wants to buy? Justify how you reasoned your answers. thats what it asks and I'm still confused on how i would tell him how to shop wisely etc.

Answer 55

@misty1212

Answer 56

did you solve the equation ?

Answer 57

x=5?

Answer 58

yeas good work

Answer 59

now lets go slow ok?

Answer 60

kk

Answer 61

C is the graph @DanJS

Answer 62

a) if they buy 5 charms, they pay the same amount of money, they pay $160
we computed that already in an earlier problem
b) if they by less than 5, the one that cost \(85+15x\) will be cheaper, because the the price with no charms is cheaper, and it take up until 5 to make the price the same as the other one
c) if they buy more than 5, the one that cost \(100+12x\) is cheaper, because that one cost less per charm

Answer 63

why u need me?

Answer 64

graph for C

Answer 65

you figured the cost function C as a function of number of charms x

C(x) = 15x + 85

Answer 66

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.

Answer 67

\[$85 \le c(x) \le $250\]

Answer 68

equation for the graph?

Answer 69

What is the flyer for? that is part e) right

Answer 70

yes

Answer 71

ok, ill graph it , one sec

Answer 72

thanks :D

Answer 73

the red line is the cost function

y-axis is the cost
x-axis is # charms

for the cost to be between 85 and 250, the number of charms has to be between 0 and 11

Answer 74

that look alright to you?

Answer 75

Yes :D omg thanks soo much :D