please help me with this math question

[pige77]

the average number of people attending a local church on sunday dropped from 265 in october 2008 to 169 in october 2009. find the rate of change

 

[wjm11]

the average number of people attending a local church on sunday dropped from 265 in october 2008 to 169 in october 2009. find the rate of change

"Rate of Change" means slope. Plot these two points, (2008, 265) and (2009, 169), on a graph and draw a line through them to visualize the problem. Can you find the slope using these two points? Tell us your thoughts and where you are stuck.

 

[pige77]

"Rate of Change" means slope. Plot these two points, (2008, 265) and (2009, 169), on a graph and draw a line through them to visualize the problem. Can you find the slope using these two points? Tell us your thoughts and where you are stuck.

I am using 265 - 169 = 96
then I am dividing it by 365 days in a year which is october 2008- october 2009
I am not sure if i am doing it right that way.

 

[wjm11]

I am using 265 - 169 = 96
then I am dividing it by 365 days in a year which is october 2008- october 2009
I am not sure if i am doing it right that way.

You are on the right track, but make sure you keep track of (x1,y1) and (x2,y2) when you calculate slope so that you end up with the correct sign. You haven't shown the answer to your calculation yet, so I'm not sure if you are doing this. Also, it is probably not necessary to use 365, unless you were instructed to state the answer in terms of "people per day." You could simply use 2009 - 2008 = 1, and state your answer in terms of "people per year." Make sense?

 

[pige77]

You are on the right track, but make sure you keep track of (x1,y1) and (x2,y2) when you calculate slope so that you end up with the correct sign. You haven't shown the answer to your calculation yet, so I'm not sure if you are doing this. Also, it is probably not necessary to use 365, unless you were instructed to state the answer in terms of "people per day." You could simply use 2009 - 2008 = 1, and state your answer in terms of "people per year." Make sense?

The average number of people attending a local church on Sundays dropped from 265 in October 2008 to 169 in October 2009. Find the rate of change in attendance at church. This is the full question. I took 265-169=96 then took 96 and divided it by 365 and got .263013698 I moved the decimal over two spots to the right and got 26% is this the correct way and answer? but if I do it your way y2-y1 / x2-x1 = 265-169 / 2008-2009 = 96 / 1 which equalls 96. I am not sure which way I need to go with this problem. Is the first one or second one right?

 

[HallsofIvy]

Before you can give a rate of change you have to specify "rate of change with respect to what?". Here it is obviously with respect to time, but what units do you want to measure time with? If the problem as for per day then, yes, it dropped by 96 people in 365 days so the rate of change is -96/365= -0.263 "people per day" but if the problem is per year then the rate of change would be -96 people per year. Which is correct depends on exactly what the problem is. Just "find the rate of change" is not enough to tell which is wanted. One error you are making is giving a positive rate of change. Since the number is decreasing, its rate of change is negative.

 

[pige77]

Before you can give a rate of change you have to specify "rate of change with respect to what?". Here it is obviously with respect to time, but what units do you want to measure time with? If the problem as for per day then, yes, it dropped by 96 people in 365 days so the rate of change is -96/365= -0.263 "people per day" but if the problem is per year then the rate of change would be -96 people per year. Which is correct depends on exactly what the problem is. Just "find the rate of change" is not enough to tell which is wanted. One error you a re making is giving a positive rate of change. Since the number is decreasing, its rate of change is negative.

Thank you for the help. I understand what you mean by the dfference in "per day" or "per year".

 

[pappus]

Thank you for the help. I understand what you mean by the dfference in "per day" or "per year".

Since the question is about services in church I would choose "week" as the appropriate unit of time.

(If you take year as unit of time then you are refering to the yearly Christmas service and
if you take day as unit of time you probably live in a monastery (or convent))

 

[mmm4444bot]

if I do it your way (y2-y1) / (x2-x1) = (265 - 169) / (2008 - 2009) = 96 / 1 which equalls 96.

You made an arithmetic mistake above.

2008 - 2009 = -1

Anytime you subtract a larger number from a smaller number, the answer will be negative.

(On the Real number line, larger numbers always appear to the RIGHT of smaller numbers.)

96/(-1) = -96

The answer to your exercise is -96 people/year. :cool: