A mathematical challenge for you all.....

[AuntyQuated]

Problem of the day---

me and a friend were in M&S today she had 2 things in her basket - one for £12 and one for £15

in my basket were 4 things for £8, £10, £10, and £10.

to get the best deal from the "2 for 3 offer" my friend paid for 3 items of £15,£10 & £10. so she paid £25

i paid for 3 items of £12,£10 and £8. i paid £22

BIG QUESTION

how much do i owe her??? (we want to share the discount)

every time we work it out we come up with a different answer.
please someone..put us out of our misery>

if you give her £1.50 then you both paid £23.50 ..... i think? (I'm crap at maths!!!!! )

(thats the easy way out without working it out for each item )

Her original price -- 27 GBP
Your original price -- 38 GBP

She paid: 25 GBP saving 10 GBP
You paid: 22 GBP saving 8 GBP

Total savings: 18 GBP

If you want to split the savings (ie 9 GBP each), then you should have paid 29 GBP.

If you want the savings to be proportional to your total spend, then you'd save 38/65(18 GBP) = and she'd save 27/65(18GBP) which means you should have saved 10.52 GBP and you should have paid 27.48 GBP and would her 5.48 GBP

Sorry -- that's just typing without thinking.. might be a mistake or three in there! And I don't have a pound key.

but i got 4 itmes,valued at £38 and she got 2, valued at £27

You got £18 off in total so £9 saving each? I think you owe her £9 but I'm also useless at maths, sorry .

so jj...i ought to give her £7, that was one of the answers we came up with

Blimey JJ I think you are slightly better than me at this.

Sorry! Thought you were splitting the discount. Then she should have paid 27 GBP and you would get the entire discount, so she owes you 2 GBP.

I would add the two cheapest items from each 3 together to find the total saved, and then then halve that to find the saving each (assuming you want to split it equally).

So in total you saved £10 +£8=£18, which is £9 saving each. For your friend the value of her goods was £12 + £15=£27, subtract her saving which £9 and you get what she should have paid (£18). She actually paid £25, so you owe her the difference (£7).

Oops, yes, AQ, if you want to split the discount, you'd owe her 9 GBP. Sorry for crossposting.

(Bagpuss, this relates to what I did in a previous life... )

Bloody hell, that obviously took me much longer than everyone else, there were no other posts when I started.

i can feel my head is about to explode at the thought of working this out

yes we want to split the difference but wouldn't that be i owe her £7 JJ?

God, I don' t think I have enough fingers and toes for this .

I make it £7 AQ

give her £7 a be done with it

if she's a true friend she won't quibble of the (possible) other two quid

give her £8!!??

"over the (possible) other two quid"

Oops, sorry, I mis-typed! And small son jumped off couch onto hard floor and phone range. Yes, 7 GBP.

Total discount was £18 - i.e. £9 each shared.

Your goods were worth £38, less £9 discount = £29. You paid £22, so give her £7 and you're square.

her goods worth £27, less £9 discount = £18. She paid £25 so will be all settled when she gets your £7.

oh, this is reassuring...we aren't the only ones to struggle with it.
really the money doesn't matter one bit; it's the fact that we can't work it out

I follow JJ's approach, except that I would take the view that AuntyQuated's original price would have been £30 for 4 items, and not £38, as she would have been eligible for a discount of £8 in any event.

So by joining together you got an extra £10 discount. If you were splitting this equally then Auntyquated should have paid £25 and her friend £22 (so basically they took the wrong baskets!). AQ should pay her friend £3.

You could pro-rate the saving, but this amounts to 27p difference, so I'd keep it simple (envisioning another debate about which coins you have in your purse!)

And phone range ? argh.

I like Ladymuck's way better, fwiw.

Am off to find small son... has disappeared again.

Next time please go shopping on your own, not with your friend, and save us all some headaches!