Question

Need help with a word problem.

Answer 1

Hello there.

Answer 2

Hi

Answer 3

What's the word problem?

Answer 4

Here it is: A multi-year analysis was begun in 1987 to determine the percentage of American women claiming to be on a weight-loss diet.
6 years into the study, 16% of women were found to be on a diet, while 12 years into the study, 12.5% of women were found to be on a diet.

Use this information to find the equation of the line that models this data.
Let y = percentage of women on a diet, and let x = number of years into the study.
Give the point-slope form and the slope-intercept form.

Answer 5

So I know that I first need to find the slope.

Answer 6

By subtracting/dividing the two points (6,16) and (12,12.5)

Answer 7

What I got was -3.5/6....which doesn't seem to be right.

Answer 8

This is the full eq'n I have y -16 = -3.5/6(x-(12.5)) The LHS is right, but the rest is apparently wrong.

Answer 9

You are jumping over yourself here.

Answer 10

Oh?

Answer 11

Say 1987 is the starting point.

Answer 12

Yep.

Answer 13

You can label this on a x-y graph.

Answer 14

now 6 years into the study, make the year the x axis

Answer 15

Umm...okay, the thing is...the method displayed on our website doesn't involve graphing...so yeah. Are you sure that'll really be necessary?

Answer 16

Its up to you. I think if you can see what you are working with, you are less likely to make a mistake. Its totally up to you.

Answer 17

I kind of prefer to avoid graphing, honestly.

Answer 18

Like...I'd mostly just like to know what mistakes I made in my calculations.

Answer 19

ok

Answer 20

I think I see your mistake

Answer 21

Oh? What exactly is it?

Answer 22

So, you got the slope correct, but the points are (6, 16) and (12, 12.5)

Answer 23

Right.

Answer 24

Do you see what i'm referring to?

Answer 25

Um...no, I'm afraid I don't.

Answer 26

Ok, so when you use the point slope formula, you only need one point, It looks like you used 2 coordinate points with the wrong value

Answer 27

instead of 12.5 you needed to plug in 6

Answer 28

Oh...yeah, you're right. :)

Answer 29

That should fix your issue.

Answer 30

Alright, thank you very much, sir :)

Answer 31

Have a good night/day!

Answer 32

sure.