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Maths when out Shopping

August 31, 2011

What maths did I spot when out shopping today?


The 2 books for £5 is rather a good WHSmith deal. If you zoom in on the labels on the books, you’ll see they are £4.99 each anyway! I suppose the question here is why not just go with buy one, get one free?


The sports shop that had the balls for sale speaks for itself. If you zoom in, there’s a (relatively) tiny ‘up to’ in the top left corner.


The final one was in M&S and is a powder compact although the picture has not come out well.
The £7.50 sticker has small writing on that says £150 per 100g. This will lead to the question of how much powder does that mean you’re getting? Also, how does this compare to something like gold or spices per 100g?

Quite a bit of maths out there (and see the previous post too).



From → Uncategorized

  1. Max Stone permalink

    Of course, technically the second book costs 1p, which is of course technically different to a BOGOF offer, I would imagine it’s due to the clarity of the marketing. 2 for ??5 makes it clear how many books you get for how much money. Using BOGOF would mean the customer would have to look closer to find how many books they’d get for their money.

  2. Anonymous permalink

    Indeed, but I doubt those 1ps makes a huge difference the WHSmith’s profits ;-)Sign could read:"Books ??4.99 eachBuy one get one free"Again, this is much more of a business studies/psychology question than a maths one. It still interests me though.

  3. Max Stone permalink

    Agreed. However, I feel the 2 for ??5 is that much more succinct, allowing the text to use a bigger font size in the same area as would be required for your alternative wording. So you’ve got a quicker and clearer message. The critical point being presumably, which is more enticing; 2 books for ??5 or a free book for each book you buy at ??4.99?What I find interesting additionally, is the use of ??5 rather than ??4.99. While I agree with you, the 1p as a purely financial element is unlikely to have been the reason (even factoring in the number of books sold and the number of 1ps that would add up to), it seems a rare sight to see a price that hasn’t been rounded down by a penny (or a pound – depending on the sort of price) to create the psychological effect of making the price look much cheaper than it really is. One can only assume that clarity and conciseness were more important elements than the price.Another example of this sort of thing I have seen was an offer for a Pizza for 1p but only when you purchased another pizza of the same or greater value. Presumably people are more drawn to the offer of a pizza for a penny than they are to a BOGOF offer.

  4. Ihor Charischak permalink

    My take on the 2 for 5 pounds deal: I think the "get one free deal" is a bit misleading… see my comment about a related shopping offer <a href="">Those #?%& Supermarkets: They’re Out to Catch You</a>-Ihor

  5. Max Stone permalink

    My comment on Ihor Charischak’s: Those #?%& Supermarkets: They’re Out to Catch YouWould that not only be the case if the price of the strawberries had been put up from $2.00 (or $1.99) to $3.99 for the duration of the offer? If the strawberries are normally $3.99 and you only get a free box for a limited period, then the additional box is actually free. After all, if you only take one box, you still pay the same price (you don’t actually have to take the second box, but your alternative sign says you do).I think the bigger issue with offers like these is the waste. Very few (if any) people would take only one box, when there is no additional cost to taking a second. However, as you say, people may not eat the second box, which would just be a waste of food. Alternatively, they may eat it purely to avoid wasting it, resulting in eating to avoid waste rather than because they actually desire the second box.In either case, it’s not a positive outcome.These sort of offers (in my opinion) are designed to draw customers in. They then go on to spend money on other goods that they may have been able to get cheaper (overall) in another store, albeit one that doesn’t lose money running offers like this.

  6. Ihor Charischak permalink

    My comment on Max Stone’s reply in <a href="">my blog entry</a>: I agree that it’s a big waste. This is the kind of discussion middle school kids should have in math class. A really good and honest real world problem.

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