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

You are not logged in.

#1426 2014-07-25 07:37:52

mandy jane
Member
Registered: 2010-09-23
Posts: 1,003

Re: Mandy Jane's Corner

Hi I will work on this question and get the answer back to you tomorrow ok

Offline

#1427 2014-07-25 07:43:45

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

Okay I agree let us leave it a day.

EDIT:

Answer to Q3 for the record: 212.62125/500 = 0.4252425
Multiply by 100 to convert to a percentage: 42.52425% which rounds to 43%


Since Q4 is slightly easier than Q3 and similar you might like to attempt Q4.
I will leave it up to you. Take your time and try to get the answer correct.

Last edited by SteveB (2014-07-26 08:11:25)

Offline

#1428 2014-07-26 08:12:35

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

Mandy. Are you okay? Are you still continuing this?
Perhaps continue on Monday?

EDIT:

Consider a series of Os and Xs:

OOOOOOOOOO
OOOOOOOOOO
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX

Each row has 10 of the letter. Two fifths of these are Os and three fifths are Xs.
Imagine that there were two lots of that ie:

OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX

Out of 100 there are 40 Os and 60 Xs. So as a percentage there are 40% Os and 60% Xs.
You could do 2/5 = 0.40     then x 100 -> 40 %
and then 3/5 = 0.6       then x 100 -> 60 %

Now try answering Q4 with that method and round the answer off.

Okay I will reveal the answer to Q4:

I am getting: 9/29 = 0.31034... = 31.034...%
Rounded to the nearest percentage 31%


I am getting 7.5 / 29 = 0.258620..... = 26% rounded to the nearest percentage.







I will go through the other questions for completeness....
I apologise in advance if there are any mistakes.

The rate part of the question involves a cost of £3 per cubic metre and 120 cubic metres used.
So we do: £3 x 120 = £360
The standing charge added on is £100 regardless of other costs so:
£360 + £100 = £460
Then an allowance for VAT at 20% has to be made so:
£460 x 1.20 = £552






First observe that 13000 kWh has been used and divide by 1000.
This is because the rate is 47.50 per 1000 kWh.
So we do £47.50 x 13000 / 1000 = £617.50
Then add the yearly standing charge of 150:
£617.50 + £150 = £767.50
Then add 20% VAT:
£767.50 x 1.2 = £921







I am getting (37 x £7) + ( 2 x £9 ) = £277

I am getting £259 x 4 = £1036

£277 x 48 = £13296 for the amount excluding holiday pay
£13296 + £1036 = £14332

£4332 is taxable

£4332 x 0.2 = £866.40


Last edited by SteveB (2014-07-29 02:07:42)

Offline

#1429 2014-07-28 06:23:29

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

Let's revise percentages. Don't worry about those above questions Mandy.

Here are a few examples of O and X percentages where the number of letters rather than the area is of concern.
Since the letters have different widths I will stick to the same length of row in each case in terms of the letters.

This is a case of 10% Xs and 90% O

XXXXXXXXXX
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO

Of course since percentages are a measure of proportion there don't have to be 100 items as such:

X
OOOOOOOOO

If you have the above situation then there are 9 Os and 1X there so the proportion of Xs is still 10%
and the proportion of Os is still 90%

If you have this:
OO
XX

The proportions are 50% X and 50% O

You could expand this to:
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX

So there are 5 lots of ten of each. So there are 50 Os and 50 Xs meaning 50% O and 50% X.
I will leave it there for now. You have some reading to catch up on. I will leave you to it.

One question for you to try:
What are the percentages in this case:
OOO
XXX
XXX
XXX

What percentage of those are Os ? What percentage of those are Xs ?

EDIT: Another hint:

OOOOOOOOOO
OOOOOOOOOO
OOOOOXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX

Last edited by SteveB (2014-07-29 07:04:55)

Offline

#1430 2014-07-28 06:35:29

mandy jane
Member
Registered: 2010-09-23
Posts: 1,003

Re: Mandy Jane's Corner

Hi 3% are 0 and 9% are X am I right send me a message back please

Offline

#1431 2014-07-28 06:40:29

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 16,251
Website

Re: Mandy Jane's Corner

That is not correct.

Hint: try to express it as a fraction first


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

Offline

#1432 2014-07-28 06:44:00

mandy jane
Member
Registered: 2010-09-23
Posts: 1,003

Re: Mandy Jane's Corner

Hi  mandy here if it is a fraction would it be 3/9  then am I right send me a message back please

Last edited by mandy jane (2014-07-28 06:45:02)

Offline

#1433 2014-07-28 21:10:10

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

3% and 9% cannot be correct because the total of these two percentages is 12% and the two should add up to a whole namely 100%.
You could try expressing it as a fraction first that would be my method as well.

Last edited by SteveB (2014-07-29 02:12:36)

Offline

#1434 2014-07-28 21:11:46

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

You are getting warmer but that still does not work.
The total of all of them is 12 so the thing on the lower part of the fraction has to be the amount that it is out of.

Offline

#1435 2014-07-28 21:13:31

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

The answer obtained by 3/9 would be 33.333.... % which is not right.

The denominator (bottom of the fraction) is the whole of them.
The numerator (top of fraction) is the "partial bit" of the proportion in each case.

Try again ?

Reminder of the question:

Let us call this Question (1):

What are the percentages in this case:
OOO
XXX
XXX
XXX
What percentage of those are Os ? What percentage of those are Xs ?

ANSWER: 25% are Os and 75% are Xs.
I was wanting to see something like this:
total number of items = 12
3/12 = 0.25
9/12 = 0.75
0.25 = 25%
0.75 = 75%

EDIT: Please refer back to post number #1429 at the end of the post.

Another question:

Let us call this Question (2):

What percentage of these are Xs ?

XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO

Each row has exactly ten items in and the total is 100.

ANSWER:
Since the total is already 100 by inspection 30% are Xs and 70% are Os

Here are four questions on percentages for you:
Question (1)
Using 100 symbols in total which are either Xs or Os represent the percentage 40% Xs and 60% Os


Question (2)
What are the percentages of Xs and Os in this diagram?
XXXXXXXXXX
XXXXXXXXXX
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO
OOOOOOOOOO


Question (3)
Using only 4 symbols in total represent 25% Xs and 75% Os


Question (4)
What percentages of Xs and Os are represented by this diagram?
XX
OO

Last edited by SteveB (2014-08-06 00:02:36)

Offline

#1436 2014-08-06 13:59:52

mandy jane
Member
Registered: 2010-09-23
Posts: 1,003

Re: Mandy Jane's Corner

Hi Steven or any one else
Question 1    using 100 symbols in total which are either Xs or Os represent the percentage 40% Xs and 60% Os

0000000000
0000000000           =40% are Os
0000000000
0000000000
Xx xx xx xx xx
Xx xx xx xx xx
Xx xx xx xx xx    60% are Xs
Xx xx xx xx xx
Xx xx xx xx xx
Xx xx xx xx xx

Question 2    what are the percentage of Xs and Os in this diagram

xx xx xx xx xx
Xx xx xx xx xx
0000000000
0000000000
0000000000
0000000000
0000000000
0000000000
0000000000
0000000000

20% are Xs
80% are Os

Question 3   using only 4 symbols in total represent 25% Xs and 75% Os

Need help with this one please?

Question 4   what percentage of Xs and Os are represented by this diagram

Xx

00

2% are Xs
2% are Os

Am I right can anyone let me know please?

Offline

#1437 2014-08-06 14:07:23

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 85,347

Re: Mandy Jane's Corner

There are 2 X's and 2 O's that means out of 4 symbols 2  are X, so 2 / 4 = 1 / 2 which is 50%


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#1438 2014-08-06 14:16:43

mandy jane
Member
Registered: 2010-09-23
Posts: 1,003

Re: Mandy Jane's Corner

Hi bobbym mandy here do you know the any of the answers to any of the other questions or not? Send me a message please

Offline

#1439 2014-08-06 14:20:37

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 85,347

Re: Mandy Jane's Corner

Hi; I gave you that hint because you are asking but I would rather not interfere with what Steve is doing with you. pappym used to say, "too many cooks spoil the broth," meaning that too many people trying to help, each with different styles will only confuse you. That would not be good.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#1440 2014-08-06 21:52:29

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

Let us have a look at question 4 and think about it in a different way:

We had 4 symbols in total namely:

XX
OO

Now let us imagine that we repeat those four items until there are 100 symbols:

XXOO XXOO XX
OO XXOO XXOO
XXOO XXOO XX
OO XXOO XXOO
XXOO XXOO XX
OO XXOO XXOO
XXOO XXOO XX
OO XXOO XXOO
XX OOXX OOXX
OO XXOO XXOO

There are 100 symbols altogether.

There are 25 pairs of Xs so there are 50 Xs.
There are 25 pairs of Os so there are 50 Os.

I conclude that 50% are Xs and 50% are Os.

Offline

#1441 2014-08-06 22:00:53

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

Question 3 was probably the most tricky for you,
but if you think about it if you have
"Using only 4 symbols in total represent 25% Xs and 75% Os"
then we want to end up with 4 symbols in total.

So what is 25% of 4 items? Well the answer is 0.25 x 4 = 1
So we have only 1 X

Now what is 75% of 4 items? Well the answer is 0.75 x 4 = 3
So we have only 3 Os

So the answer is XOOO

Last edited by SteveB (2014-08-06 22:01:44)

Offline

#1442 2014-08-06 22:01:08

mandy jane
Member
Registered: 2010-09-23
Posts: 1,003

Re: Mandy Jane's Corner

Hi Steve mandy here was I right with the other questions or not?  Can you let me know please?

Offline

#1443 2014-08-06 22:04:59

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

I am going to class questions 1 and 2 as correct with full marks.
With question 3 you did not manage to end up with a representation so no marks for that I'm afraid.
With question 4 you would only be right if there were another 96 symbols knocking about somewhere so I will class that as a good effort, but wrong.
So 2 out of 4 correct.

Offline

#1444 2014-08-06 22:08:02

mandy jane
Member
Registered: 2010-09-23
Posts: 1,003

Re: Mandy Jane's Corner

Hi Steve is that good or not? Let me know please?

Offline

#1445 2014-08-06 22:19:32

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

I think that you have made a good effort with your answer especially questions 1 and 2, but maybe you got a bit tired towards the end and didn't do so well with questions 3 and 4.
The point is: Do you now understand percentages or do we need to give you some more questions to test your understanding? I would say that we do.

Last edited by SteveB (2014-08-06 22:21:57)

Offline

#1446 2014-08-06 22:21:09

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

How about this for instance XXXOOOOOOO

There are 3 Xs and 7 Os there.

What percentage are Xs and what percentage are Os ?

Offline

#1447 2014-08-06 22:23:57

mandy jane
Member
Registered: 2010-09-23
Posts: 1,003

Re: Mandy Jane's Corner

Hi Steve could I have some more percentage questions please to do?

Offline

#1448 2014-08-06 22:30:44

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

Okay Mandy I will make up some new questions. The first one can be the one in post 1446. I may need half an hour at least to make up some questions.

Offline

#1449 2014-08-06 22:32:50

mandy jane
Member
Registered: 2010-09-23
Posts: 1,003

Re: Mandy Jane's Corner

Ok Steve I will be back later today as I have to work this afternoon ok?

Offline

#1450 2014-08-06 22:44:20

SteveB
Member
Registered: 2013-03-07
Posts: 557

Re: Mandy Jane's Corner

Question (1) Consider the following 10 symbols : XXXOOOOOOO
There are 3 Xs and 7 Os
What percentage are Xs ?
What percentage are Os ?
Draw a diagram with 100 items if it helps.

Question (2) Consider the following diagram:
OOOOOXXXXX
OOOOOXXXXX
OOOOOXXXXX
OOOOOXXXXX
OOOOOXXXXX
There are 50 symbols in total. Imagine that there were twice as many and in the same proportion.
What percentage are Os ?
What percentage are Xs ?

Question (3)
Draw a diagram that represents 25% Xs and 75% Os
The total number of symbols must be 8.

Question (4)
Draw a diagram in which 40% are Xs and 60% are Os.
The total number of symbols must be 20.

I will send you an email copy of that lot just in case it is easier to see in an email.

Last edited by SteveB (2014-08-06 22:45:38)

Offline

Board footer

Powered by FluxBB