Question

The price of products may increase due to inflation and decrease due to depreciation. Derek is studying the change in the price of two products, A and B, over time.

The price f(x), in dollars, of product A after x years is represented by the function below.

f(x) = 10250(0.63)x

Part A: Is the price of product A increasing or decreasing and by what percentage per year? Justify your answer. (5 points)

Part B: The table below shows the price f(t), in dollars, of product B after t years.


t (number of years) 1 2 3 4
f(t) (price in dollars) 4300 1849 795.07 341.88

Answer 1

Which product recorded a greater percentage change in price over the previous year? Justify your answer. (5 points)

Answer 2

Is this an exam?

Answer 3

no its the study guide

Answer 4

could you help me?

Answer 5

Do you still need help?

Answer 6

yes

Answer 7

Okay, I am really sorry, but I have to eat. Though, I can explain this question perfectly to you. So, I'll be back in like 20 to 30 minutes - i hope thats okay.

Answer 8

that is totally fine im just studying had a question on this problem

Answer 9

I am back. Sorry for being three minutes late.

Answer 10

its ok haha

Answer 11

Okay, I shall help you now. Let me start:

Answer 12

When it doesn't say that "Kewlgeek555 is typing a reply..." it is because I am thinking or doing work. ;]

Answer 13

Part I:
You know that this function is DECREASING because 0.63, the number inside of the parenthesis, is LESS THAN THE NUMBER 1. I [think I] know the way to determine by what percentage it is decreasing. [I think] My teacher taught me that I have to subtract the number, in this case 0.63, from 1. So, 1 - 0.63 = 0.37. So it is decreasing by 0.37.

Part II:
Wait, what are the directions asking you to do???

Answer 14

Which product recorded a greater percentage change in price over the previous year? Justify your answer. (5 points)

Answer 15

Okay, this is for the table in Part B, correct?

Answer 16

correct

Answer 17

And is this the table of Part B:


Is this correct? Also, I have to go do soemthing for my job, be back in like less than ten minutes, more than five minutes.

Answer 18

t (number of years) 1 2 3 4
f(t) (price in dollars) 4300 1849 795.07 341.88

Answer 19

I am back. I am still confused. Do you have a picture or something? But, now I think I understand A LITTLE. Is this correct?:

Answer 20

yup

Answer 21

Okay. Then, I think it is year 1 - 2.

Answer 22

can you prove it?

Answer 23

Well, I subtracted years 1 - 2, 2 - 3, 3 - 4, and 1 - 2 was the greatest difference. I just didn't want to because what I said right there is a horrid "prove it" sentence. So, I can't really prove it.

Answer 24

NO, no. Actually, they are all changing by the same percentage: 43% less. And you can prove it by dividing year 2 to year 1 and dividing year 3 to year 2. Sorry for the inaccurate answer.

Answer 25

OOOOOOO I see

Answer 26

do you think you could help me with 1 more question?

Answer 27

Belinda wants to invest $1000. The table below shows the value of her investment under two different options for two different years.


Number of years 1 2 3
Option 1 (amount in dollars) 1300 1690 2197
Option 2 (amount in dollars) 1300 1600 1900

Answer 28

Part B: Write one function for each option to describe the value of the investment f(n), in dollars, after n years. (4 points)

Part C: Belinda wants to invest in an option that would help to increase her investment value by the greatest amount in 20 years. Will there be any significant difference in the value of Belinda's investment after 20 years if she uses option 2 over option 1? Explain your answer and show the investment value after 20 years for each option. (4 points)

Answer 29

Where is Part A? Please tag me as several people are requesting help right now. D:

Answer 30

All i really need to know is the percentage of what option 1 is growing at

Answer 31

Part A: What type of function, linear or exponential, can be used to describe the value of the investment after a fixed number of years using option 1 and option 2? Explain your answer. (2 points)

Answer 32

i already did that part

Answer 33

Oh, oh, okay. Well, um. Hm...do you have the function equation? Or the value at year 0?

Answer 34

there is no year 0

Answer 35

Okay, so did you make a function?

Answer 36

I just need to know at what percentage option 1 changes at

Answer 37

Thats all I need to do

Answer 38

I can do the rest after that

Answer 39

This also seems to be a constant rate of growth. Year 2, 1690, is year 1 times 1.3. And year 3, 2197, is year 2 times 1.3. So, the rate of growth must be 130% of year 0, or in other words f(0) * 1.3.

Answer 40

I hope I'm not confusing.

Answer 41

what is the rate of chagne of option 1 as a percentage

Answer 42

Okay, I don't know now. My mind is like something else today. Let me call @jigglypuff314 @texaschic101 @agent0smith @terenzreignz for you.

Answer 43

I'm not too good at this either ;)
http://www.ehow.com/how_8117999_exponential-equation-two-points.html
I got that the equation for option 1 is d = 1000(1.3^n)
if that helps...

Answer 44

I figured it out thank you guys :D

Answer 45

wht did you get cause i got the same problemand im so lost

Answer 46

Lies. This IS an exam. *smh*

Answer 47

The only way you would know that is by looking up the question during the test as well @Secret-Ninja

Answer 48

not really she could have seen this question and remembered on her test...right @secret-ninja