Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**Freelancer_Man****Guest**

I need to work out an average for my maths homework but i tottaly forgot how and my parents are out so i cant ask them. PLEASE HEALP ME!

**Freelancer_man****Guest**

Freelancer_Man wrote:

I need to work out an average for my maths homework but i tottaly forgot how and my parents are out so i cant ask them. PLEASE HEALP ME!

i need to work out the average of these numbers. 20 20 20 20 10 40 60 10 60

**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 16,065

Hi Freelancer_man,

Welcome to the forum.

This is how the average or mean is computed.

Find the sum of all the numbers.

You get 260.

Divide it buy the number of quantities (in this case, numbers).

i.e. 9.

The average is 260/9 or 28.888888888888888.........

rounded off to 28.89.

In general, average or mean of a,b,c,d,e,f is

(a+b+c+d+e+f)/6. There are six quantities a,b,c,d,e,f. Therefore, the sum is divided by 6. Clear?

Character is who you are when no one is looking.

Offline

**Mark.S****Guest**

Thankyou very much Ganesh!

I don't know much maths, but I needed to work out an average and it took me 10 seconds to find this on google. Thankyou!

**Alexandra Jackson****Guest**

Im working out the average speed of a graph about a lorry, and im given a constant line so there are no persific numbers to add up and divide.

I am totally confused as to how to do this :S

Please help and reply to my email if possible

Yours thankfully Alexandra.

**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

It sounds like you've got a distance-time graph there. If so, then just pick any point on the line and divide the distance co-ordinate by the time one.

Why did the vector cross the road?

It wanted to be normal.

Offline

**Charlotte****Guest**

hey can someone please help me out a little.

gotta find the average of these numbers:

80, 78, 60

and then to find out the average of these numbers too:

29,30,20

if anyone can help would be much appreciated:D

**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

As ganesh said, the average of a group of numbers is found by adding all the numbers together and then dividing by however many numbers there were.

So for example, the average of 80, 78 and 60 would be (80+78+60)/3 = 218/3 = 72 2/3.

Why did the vector cross the road?

It wanted to be normal.

Offline

**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,585

I'll do the 29 + 30 + 20 divided by 3 one another way: answer = 26 and 1/3, but how another way?

Well, do this:

29 30 20

make 30 go down 5 and 20 go up 5, so

29 25 25

Then make 25 and 25 go up by 1 each and 29 go down by 2, so

27 26 26

Then make 26 and other 26 go up 1/3, and then make the 27 go down 1/3, but then 1/3 more down again.

So then,

26 1/3 26 1/3 26 1/3

That's the answer when they are all the same.

**igloo** **myrtilles** **fourmis**

Offline

**Chris111****Guest**

Brilliant, helped me so much.

**glenn101****Member**- Registered: 2008-04-02
- Posts: 108

What I really like about this post is that it helped out not only the person with the problem but LOTS of other people who are signed up on this site or not. There has been 20596!!! views, it has helped many! good work everyone!

"If your going through hell, keep going."

Offline

**X_alicia_X****Guest**

heyaaaa

ta for that guys^^^^^

it proper helps (Y)

xo:D:lol:::cool:

**fieldsy****Guest**

ummmm i don't know if this is different to others but can someone please find the average between -67 and 37

Much appreciated:D

**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 16,065

fieldsy,

It isn't different in any way!

Just add the two numbers and then divide them by 2:-

Character is who you are when no one is looking.

Offline

**MonUment****Guest**

how do you work out average of times?

**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

Averages of times are worked out in the same way a normal average.

If you run a race three times and get times of 13s, 17s and 16s, then your average time was (13+17+16)/3 ≈ 15.3s.

Why did the vector cross the road?

It wanted to be normal.

Offline

**tonybaynes****Guest**

I would like to work out an average size of a product in an invoice, for instance:

1/2kg = 6000kg

2/3kg = 2000kg

3/4kg = 1000kg

4/5kg = 700kg

5/6kg = 200kg

6kg+ = 100kg

The total = 10,000kg

What would the formula be for determining the average size, taking the average of 1/2kg = 1.5kg, 2/3kg = 2.5kg etc.?

To find out a simple average adding a series of numbers and then dividing the by number of numbers, doesn't appear to apply here.

**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

Estimate how many of each product is in the invoice, and work out the average that way.

All the items between 1 and 2kg have a combined weight of 6000kg.

Assuming their weights are uniform within the range, their average weight will be 1.5kg.

Therefore, there must be 6000/1.5 = 4000 items in that range.

Similarly, there are 2000/2.5 = 800 items in the next range, and 1000/3.5 ≈ 286 items in the one above that. Work out the rest of them, and then the [total weight]/[# of items] formula will apply.

The 6kg+ category is a little tricky, because you can't estimate an average weight for that category in the same way. I would guess an appropriate upper bound for the weight and get an average using that. Since that category has less items in it than any other, the overall answer won't be affected much by what you pick.

Why did the vector cross the road?

It wanted to be normal.

Offline

**zeynep****Guest**

i nned to find the avarage of 554,401.61. helpp me plz!!!

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,926

Hi zeynep;

Add em up and divide by 2

*Last edited by bobbym (2009-06-25 04:28:58)*

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**Jayne****Guest**

I'm trying to work out a question at work I have to find out the average number of workers over the last 24 months? I have 27 employees employed at the moment and have had 32 employees leave within the the last 24 months so how do i work out the average???:(

**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

To get an accurate answer, you'd need to know when each of the employees left.

Assuming they left at regular intervals throughout the time period though, you'd have an average employee amount of 43.

Why did the vector cross the road?

It wanted to be normal.

Offline

**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

Anyone have the faintest idea why this thread has over 35,000 views?

"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,926

Hi Rick;

That is a lot of views, I guess averages are interesting and important to a lot of people.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**Avon****Member**- Registered: 2007-06-28
- Posts: 80

Ricky wrote:

Anyone have the faintest idea why this thread has over 35,000 views?

This thread is the first page that comes up when I search for its title (or even just 'work out average') on Google.

Offline