Help needed

[20lilly02]

Hi everyone,
I have had someone I know approach me to ask how to tackle this maths task (I am primary school trained so this is way above what I am trained for).

I have explained this to him, but he’s desperate and college sessions have been sporadic (no thanks to Covid).

It has me stumped, to be honest I’m not wholly convinced it actually makes sense.
Could someone please take a look, I’m not after an answer to it, I would just like clarification on if it is doable and what to research/look up to help him and/or pass on to him.

Thank you in advance

 

[Cubist]

It has me stumped, to be honest I’m not wholly convinced it actually makes sense.

Which part of the question has you stumped? If you tell us then we will be able to help you more effectively.
Is the constant value "A" confusing? Are you stuck on part a or b? Please let us know and hopefully we can help.

 

[20lilly02]

Which part of the question has you stumped? If you tell us then we will be able to help you more effectively.
Is the constant value "A" confusing? Are you stuck on part a or b? Please let us know and hopefully we can help.

The constant value of A mainly, maybe It is just beyond me but this seems far more advanced than a level.

 

[Deleted member 4993]

Hi everyone,
I have had someone I know approach me to ask how to tackle this maths task (I am primary school trained so this is way above what I am trained for).

I have explained this to him, but he’s desperate and college sessions have been sporadic (no thanks to Covid).

It has me stumped, to be honest I’m not wholly convinced it actually makes sense.
Could someone please take a look, I’m not after an answer to it, I would just like clarification on if it is doable and what to research/look up to help him and/or pass on to him.

Thank you in advance


View attachment 22663View attachment 22664

We strongly suggest that your friend contact us directly - so that we can provide help according to what s/he knows. There are 2 unknowns and 3 equations (given). So an important topic would be "simultaneous equations".

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

READ BEFORE POSTING​

Please share your work/thoughts about this problem.

 

[20lilly02]

We strongly suggest that your friend contact us directly - so that we can provide help according to what s/he knows. There are 3 unknowns and 3 equations (given). So an important topic would be "simultaneous equations".

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

READ BEFORE POSTING​

Please share your work/thoughts about this problem.

Sorry I didn’t realise I had broken any rules, I had read them prior to posting. As mentioned previously I am stumped I look at it and am lost so workings out are few and far between.

I’ve looked at simultaneous equations with him and I understand the method (I think! Although this has me doubting myself now!) It is the “A” that throws confusion into the mix because, if like the task suggests, you replace “A” with your birth month it renders the whole thing a nightmare for him as it’s March (3)

So the equations would read.

Equation A 3x + 2y = 3
Equation B 3x + 2y = 10
Equation C 3x + 3y = 4

Is this correct?

 

[Deleted member 4993]

Sorry I didn’t realise I had broken any rules, I had read them prior to posting. As mentioned previously I am stumped I look at it and am lost so workings out are few and far between.

I’ve looked at simultaneous equations with him and I understand the method (I think! Although this has me doubting myself now!) It is the “A” that throws confusion into the mix because, if like the task suggests, you replace “A” with your birth month it renders the whole thing a nightmare for him as it’s March (3)

So the equations would read.

Equation A 3x + 2y = 3
Equation B 3x + 2y = 10
Equation C 3x + 3y = 4

Is this correct?

Yes.

 

[Cubist]

The constant value of A mainly, maybe It is just beyond me but this seems far more advanced than a level.

Once you assign your month of birth to "A" you can just rewrite all of the equations using that value. I was born in September so A=9, and I can rewrite the first two equations

3x+2y=A
Ax+2y=10

as

3x+2y=9
9x+2y=10

Now, if I was born in March (as you have spotted) I can see a slight problem because when A=3:-

3x+2y=3
3x+2y=10

These two equations disagree with each other. In this case I'd have to use the 1st and 3rd equation, or the 2nd and 3rd equation (the question states to use two of the three equations)

 

[20lilly02]

Once you assign your month of birth to "A" you can just rewrite all of the equations using that value. I was born in September so A=9, and I can rewrite the first two equations

3x+2y=A
Ax+2y=10

as

3x+2y=9
9x+2y=10

Now, if I was born in March (as you have spotted) I can see a slight problem because when A=3:-

3x+2y=3
3x+2y=10

These two equations disagree with each other. In this case I'd have to use the 1st and 3rd equation, or the 2nd and 3rd equation (the question states to use two of the three equations)

Thank you so much for your reply, that was all I needed to hear.

Your help is much appreciated.

 

[Deleted member 4993]

Part of the question requires you to discuss "error". That is the "interesting" part of the assignment (3 equations and two unknowns).

 

[Cubist]

It does seem a poorly designed question, since anyone born in Feb or Mar will be faced with a more difficult problem (because two equations will disagree with each other).

I disagree with Subhotosh regarding the "error" part of question b because I think this relates to the accuracy of a graphing solution vs an algebraic solution... all using just two of the three equations.

Anyway, after choosing an appropriate pair of equations I think the next step (part a) is to draw two lines, on the same graph, to find the point where they intersect. Would you be able to do this?

EDIT: I'm not sure why part b says "Check your solutions..." when there will only be one solution, assuming that my interpretation of the question is correct. (At the end of the question it states "Required: written work showing all calculations to solve a pair of simultaneous linear equations using a graphical technique" this seems to confirm my interpretation.) But this is not a well designed/ clear question.

 

[20lilly02]

It does seem a poorly designed question, since anyone born in Feb or Mar will be faced with a more difficult problem (because two equations will disagree with each other).

I disagree with Subhotosh regarding the "error" part of question b because I think this relates to the accuracy of a graphing solution vs an algebraic solution... all using just two of the three equations.

Anyway, after choosing an appropriate pair of equations I think the next step (part a) is to draw two lines, on the same graph, to find the point where they intersect. Would you be able to do this?

Yes this is something I am sure I can work on with him now, I have suggested he talks to the course tutor also but he’s finding he’s not very successful!

I will try my best and hope I can help him, thank you very much for your guidance, it’s been very helpful thank you

 

[Deleted member 4993]

It does seem a poorly designed question, since anyone born in Feb or Mar will be faced with a more difficult problem (because two equations will disagree with each other).

I disagree with Subhotosh regarding the "error" part of question b because I think this relates to the accuracy of a graphing solution vs an algebraic solution... all using just two of the three equations.

Anyway, after choosing an appropriate pair of equations I think the next step (part a) is to draw two lines, on the same graph, to find the point where they intersect. Would you be able to do this?

EDIT: I'm not sure why part b says "Check your solutions..." when there will only be one solution, assuming that my interpretation of the question is correct. (At the end of the question it states "Required: written work showing all calculations to solve a pair of simultaneous linear equations using a graphical technique" this seems to confirm my interpretation.) But this is not a well designed/ clear question.

You are correct, probably. I had assumed that this problem was more geared toward teaching about "over-constraint". May be that is not quite the goal at this level.

We will get a solution if we choose equations B & C; but for any value of A (Integer 1≤A≤12), we cannot satisfy all three simultaneously. I had assumed that that would be the goal of discussion of error.

 

[Cubist]

Yes this is something I am sure I can work on with him now,

Great!

I have suggested he talks to the course tutor also but he’s finding he’s not very successful!

Be careful how you phrase this to the tutor, since they might be upset at having issues pointed out regarding a question that they may have written themselves. Remember the tutor might be marking the end-of-year exam papers. So it depends on the tutor's personality. If I was you I'd just write something simple in my answer like "Equations one an two contradict each other when A=3, therefore use equations...".

I had assumed that this problem was more geared toward teaching about "over-constraint". May be that is not quite the goal at this level.

We will get a solution if we choose equations B & C; but for any value of A (Integer 1≤A≤12), we cannot satisfy all three simultaneously. I had assumed that that would be the goal of discussion of error.

An easy assumption to make, given the question, therefore I think the spider in the corner can stay lonely today

 

[HallsofIvy]

Sorry I didn’t realise I had broken any rules, I had read them prior to posting. As mentioned previously I am stumped I look at it and am lost so workings out are few and far between.

I’ve looked at simultaneous equations with him and I understand the method (I think! Although this has me doubting myself now!) It is the “A” that throws confusion into the mix because, if like the task suggests, you replace “A” with your birth month it renders the whole thing a nightmare for him as it’s March (3)

So the equations would read.

Equation A 3x + 2y = 3
Equation B 3x + 2y = 10
Equation C 3x + 3y = 4

Is this correct?

Yes, so far. Now, do you remember that the problem said to choose any TWO equations to solve? Looking at the first two you should see immediately that the left sides are both 3x+ 2y so can't give different right sides. So choose either the first and third or the second and third equations.
The first equation is 3x+2y= 3 and the third equation is 3x+ 3y= 4. They still both have "3x". If we subtract the first equation from the second the two "3x" terms cancel and we have y= 1. Then 3x+ 2y= 3 becomes 3x+ 2(1)= 3. Subtract 2 from both sides to get 3x= 1 and then x= 1/3. x= 1/3, y= 1 satisfy the two equations.