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Thread ID: 50661	2004-10-28 06:23:00	Maths Revision	Gum Digger (5187)	Press F1

Post ID	Timestamp	Content	User
285524	2004-10-29 11:53:00	>You can's do this on a normal calculator, sorry, should be can't do this on a normal...	Bletch (244)
285525	2004-10-29 20:27:00	>You can't work out the interest this way. This is because it is not a lump sum interest, it is a compounding interest. What you need to do is take off the second year's interest, then the first years. Yes you can. Pull out your calculator, and do it my way. You'll be surprised I'm guessing to realise the answers are the same. My problem was never with the mathematics involved! Your logic is plausible, yet, given the amount of information available, possible slightly farfetched. We are all told not to assume anything in any question, so this just adds to our plight. As far as this "common sense" thing goes, would common sense not dictate that the lumpsome he pays the dealer back is 70% of the car with interest? This question is missing something as you said, and without that something we are unable to complete it, because that would be making things up, now wouldn't it? So let me get this straight - he owes the dealer 70% of the car (with interest added, but it is still the remainder of what's left to be paid). He also owes his parents 45*24=$1080. You are suggesting that one presumes that this money is intended to pay the dealer aswell. So let's look at the logic again: He originally paid the dealer 3/10 of the car (deposit). In option two he is paying back 7/10 of the car. THAT MAKES 10/10 = 1 = THE WHOLE CAR. What I don't understand is what common sense dictates that we add the payment to the parents to all of this! Following your method, we are presuming that the lumpsome paid to the dealer in method two is not all of the money remaning to be paid on the car. Your logic is probably the logic the examiners used, but because of the horribly worded question we do not know in which way to take it. Using common sense, for example, we deduced that method two concerend all of the money owed to dealer after the 30% deposit and so, because the dealer would not give a deal on say 60% of the remainder, this must be all that is owed. I mean c'mon, in reality which dealer out there gives you a payment plan in which you've paid 30%, and you delay the payment of 60%, and the remaining 10% is up to some random!? The question is flawed. That is my point. We can discuss common sense but there is always a counter-argument, which makes this question utter crap. So my point stands - no amount of working will make this question plausible or reasonable. Sure it can be done, but in so many different ways that it reaches a level of idiocy unparalled by any other question I've ever faced. And for the record, my teacher is highly capable - the fault is not hers. You all think you have the answer, but the amount of guessing and presuming you did would not get you marks in the exams (we cannot, for example, deduce that a beam horizontal to a flat ground is parallel). Pfft, cars.	Growly (6)
285526	2004-10-29 22:14:00	Let's explain in simple terms John sees a car priced $5043.43. He counts his pennies and finds he has 30% of the price as a deposit namely $1513.03. He goes to his mum and asks if see can help him out. Yes she says - I can lend you $1080 towards the car and you can pay me back at $45 per month for 2 years. That leaves the rest to be borrowed from the dealer $2450.4. Interest will be paid on this in terms of 10.5% immediately equals $2707.69 and then this sum incurs a further 10.5% equalling $2992 lump sum. All this is evident in the question.	Dally (6292)
285527	2004-10-29 22:56:00	> > You can't work out the interest this way. This is > because it is not a lump sum interest, it is a > compounding interest. What you need to do is take off > the second year's interest, then the first years. > > Yes you can. Pull out your calculator, and do it my > way. You'll be surprised I'm guessing to realise the > answers are the same. My problem was never with the > mathematics involved! True, for this instance. I admit I did not notice that the answers were the same. > > Your logic is plausible, yet, given the amount of > information available, possible slightly farfetched. > We are all told not to assume anything in any > question, so this just adds to our plight. We are not told to assume anything, but the question is useless unless we do. Therefore we must assume something. > As far as > this "common sense" thing goes, would common sense > not dictate that the lumpsome he pays the dealer > back is 70% of the car with interest? This > question is missing something as you said, and > without that something we are unable to complete it, > because that would be making things up, now wouldn't > it? No, common sense would dictate that they would not put 'the money owed to the parents' in the question unless it related to the question in some way. As the 30% has already been paid, the remaining 70% must contain botht the lump sum less the interest and the money paid to the parents. > So let me get this straight - he owes the dealer 70% > of the car (with interest added, but it is still the > remainder of what's left to be paid). He also owes > his parents 45*24=$1080. You are suggesting that one > presumes that this money is intended to pay the > dealer aswell. Yes. We assume this because there would be no point putting this in the question if the money was not intended for the dealer. > So let's look at the logic again: > > He originally paid the dealer 3/10 of the car > (deposit). In option two he is paying back 7/10 of > the car. THAT MAKES 10/10 = 1 = THE WHOLE CAR. What I > don't understand is what common sense dictates that > we add the payment to the parents to all of this! Because it is part of the question, and the 70% is the only place the money can logically go. > Following your method, we are presuming that the > lumpsome paid to the dealer in method two is not > all of the money remaning to be paid on the car. Yes. > Your logic is probably the logic the examiners used, > but because of the horribly worded question we > do not know in which way to take it. Using common > sense, for example, we deduced that method two > concerend all of the money owed to dealer after > the 30% deposit and so, because the dealer would > not give a deal on say 60% of the remainder, this > must be all that is owed. How do you figure this? Nowhere[/b[ does it say this, and we cannot simply ignore the money paid to the parents. > I mean c'mon, in reality which dealer out there gives > you a payment plan in which you've paid 30%, and you > delay the payment of 60%, and the remaining 10% is up > to some random!? If this was a real-life question, it would never happen. The point is that it was a test question designed to make you think. The NCEA people just made a shocking job of designing the question. > The question is flawed. That is my point. I fully agree. > We can > discuss common sense but there is always a > counter-argument, which makes this question utter > crap. [b]But, the counter-argument can always be defeated in this question, because to solve it any other way involves leaving out some of the data. > So my point stands - no amount of working will > make this question plausible or reasonable. Sure it > can be done, but in so many different ways that it > reaches a level of idiocy unparalled by any other > question I've ever faced. It can only be done one way that includes all the data, but the wording is such that it makes for a very confusing and ambiguous question. > And for the record, my teacher is highly capable - > the fault is not hers. Noting how much debate this question caused, I'm inclined to agree with you. > You all think you have the > answer, but the amount of guessing and presuming you > did would not get you marks in the exams (we cannot, > for example, deduce that a beam horizontal to a flat > ground is parallel). This would actually get an exam mark, for the reason that it is the only logic method I can find that includes all the data. If anyone can come up with another method that can do this, please say. > Pfft, cars. I fully agree!	Bletch (244)
285528	2004-10-29 22:57:00	again, sorry for the bold text	Bletch (244)
285529	2004-10-30 00:49:00	I just feel sorry for Gum Digger, who has had his question completely forgotten. Now here's where I stand: Bletch: You are 100% correct about the question, and 100% correct in agreeing with all of us (or most) that it is a poorly made question. Growly: You are 100% correct when it comes to how crap the question is, but Bletch's logic is correct (in terms of how he worked it out). Seeing as nobody here that is doing Level 1 could correctly answer the question first try in a way that would obtain any credit, I think everbody here must agree as to the quality of the question. Dally, nice explanation, it makes an ambiguous question look clear and simple. But that doesn't mean it is; shame on you NZQA. Just to fire the argument back up, $5043.43 is the only acceptable answer as I see it. George	george12 (7)
285530	2004-10-30 00:53:00	Oh, and because of rounding I mean that any answer around there is correct. Ie, Bletch's [b]$5046.??[b] (I forgot the decimal places).	george12 (7)
285531	2004-10-30 02:02:00	Why not test questions on a sample of teachers? Then on a sample of "examiners", Then on the ERO? I am not impressesed with the NCEA system . It looks to be a "manager's" idea of what a teaching factory should be like . Unfortunately, what NZ needs is an education system .	Graham L (2)
285532	2004-10-30 03:10:00	I used to help run quiz evenings (the ones where you have one minute to answer each quetion) and I liked to throw in the odd math problem just to see the look of horror on some faces. Here's a sample:- If a brick weighs 10kg plus the weight of half the brick. How much does the brick weigh?	Dally (6292)
285533	2004-10-30 04:50:00	> Oh, and because of rounding I mean that any answer > around there is correct. Ie, Bletch's $5046.??[b] > (I forgot the decimal places). Yes, although I also made one other slip-up at the beginning of my workings. I accidentally based the lump sum payment on [b]$2995 instead of $2992, so that plus the rounding will mean my final answer is slightly out. Any answer around that area will probably be correct though, as it is only a $3 error. Bletch	Bletch (244)
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