Y8 maths

[Tyre Smoke]

Okay, I probably could, given time and inclination,work this out for myself. But I'm half pissed and lazy.



I have a pack of cards numbered 1-20 I need to make six uneven piles adding up to the same number.

[Pints]

I always thought you were a bit older than 14.

[Tyre Smoke]

I am, my son isnt

[Pints]

[Odhran]

20
19+1
18+2
17+3
16+4
15+5?

[ATG]

The precise wording of the question is important. Are you supposed to use all the cards? If you are, then each pile needs to add up to 35, I think ... 21 x 10 / 6

[33q]

Total the individual numbers equals 210
Divide by 6
Each pile has to total 35
Start with the largest cards and distribute to total 35

20,15
19,16
18,12,5
17,11,7
14,10,9,2
13,8,6,4,3,1

[51mes]

Odhran said:

20
19+1
18+2
17+3
16+4
15+5?

Yep - thats what I would do - total the numbers up - like that and figure out how many you need in each pile - then see how you can build that number in each pile swapping numbers between piles to suit. (for example 16+4 = 20, 14+6=20) - then make them 10 and 30?

S.

[Tyre Smoke]

Thank you all.

[john2443]

Tyre Smoke said:

..... uneven piles adding up to the same number.

33q said:

Total the individual numbers equals 210
Divide by 6
Each pile has to total 35
Start with the largest cards and distribute to total 35

20,15
19,16
18,12,5
17,11,7
14,10,9,2
13,8,6,4,3,1

I think you'll find, correct me if I'm wrong, 2 is an even number

[0000]

Yeah, but 35 isn't.

I think they've been deliberately obtuse in not referring specifically to when they're talking about the number of cards in a pile or the sum of the face values. Which makes for a st question.

[john2443]

Let's assume we have to use all the cards.

6 piles, 20 cards, each pile has an uneven number of cards.

Can't have 1 card in a pile because total needs to be 35, so the only possible numbers in the piles are 3,3,3,3,3,5 - total 20.

By trial and error and excel
1,14,20
2,15,18
3,5,7,9,11
4,12,19
6,13,16
8,10,17

Not sure how a yr 8 is supposed to do it though! I can't think of a proper analytical way of doing it.

I started with 5,6,7,8,9 are the smallest set of 5 that add up
and
probably 1,14,20 being high low and middle are are good set.

and then juggled them about.

What do I win

[TwigtheWonderkid]

Tyre Smoke said:

I need to make six uneven piles

This is the bit I don't get. To me that reads that each pile needs a different number of cards in it, not that you can't have 2 or 4 cards in a pile.

But you can't have 6 uneven piles, because you'd needs six piles with 1,2,3,4,5,& 6 cards in each pile. And that would need 21 cards and you don't have 21 cards.

So I must be reading it wrongly.

[0000]

It could even (argh) mean just not a consistent number in each. So coming up with an answer where almost all have three cards in seems a fairly even spread that shouldn't be allowed.

I maintain it's a poorly worded question.

[john2443]

More AAARRRGGGHHH!

While we're at it, the question doesn't specify that there are 20 cards, only that they are numbered 1-20 so could be any number of cards, or 52 for a conventional pack, with some duplicates.

So Tyre Smoke junior could answer

As there are many unknowns in the question I have made the following assumptions
-there are 20 cards
-the number of cards in each pile is not an even number
-all the cards must be used
-only whole numbers between 1 and 20 are on the cards
-the teacher needs to take more care when setting questions

OK, maybe not the last one!

[33q]

To take this to a proper conclusion can we have the exact wording of the question?

[samdale]

TwigtheWonderkid said:

Tyre Smoke said:

I need to make six uneven piles

This is the bit I don't get. To me that reads that each pile needs a different number of cards in it, not that you can't have 2 or 4 cards in a pile.

I know the words are somewhat synonymous but it does say uneven not unequal.

Badly worded though. Why not just say "6 piles with an odd number of cards in each"? IF that is indeed what they mean.

Best answer yet to me looks like the 3,3,3,3,3,5 answer above. Yet it still makes assumptions.

[FredClogs]

"6 uneven piles" this is the problem with mixing English and maths together, ones a precise language the other isn't.

I read it as the 6 piles could not all be the same, not that they had to be all different. If I wanted the 6 piles to each have a discreet or unique amount of cards I would say that, "uneven" just implies they're not all equal to the same amount.

We've probably put far more thought into it now than the writer of the question which is why this confusion has occurred in the first place

[FredClogs]

Indeed also a "pack" of cards is 52 in number.

20 cards together is not a "pack" it's close to half a "pack".