On 11/08/19 3:06 AM, David Wright wrote: > On Sat 10 Aug 2019 at 21:19:31 (+1200), Richard Hector wrote: >> On 10/08/19 9:10 PM, deloptes wrote: >>> Richard Hector wrote: >>> >>>> <rant> >>>> Sorry, this usage grates with me. >>>> >>>> $amount cheaper that $price means subtract $amount from $price >>>> >>>> $x times $price means multiply $price by $x >>>> >>>> so "2 times cheaper (than $450)" is: >>>> >>>> $450 - (2 x $450) = -$450. >>> >>> so what multiplied by 2 gives 450? >>> >>> 450 is 100% or 1 >>> 225 is 50% or 1/2 >> >> Right, so 225 is 50% cheaper, or half cheaper. Not twice cheaper. >> >>> perhaps this is the confusion, cause we are using daily language to refer to >>> maths. >> >> Daily language is the problem, yes. I'm not saying my fight is an easy >> one :-) >> >>> In fact I would do it the other way around. >>> >>> initial price x >>> 1xtime x+(1*x) >>> 2xtimes x+(2*x) >>> >>> this gives x=150 >> >> 450 is two times more expensive than 150 (or 200% more than), or three >> times as expensive as 150 (or 300% as expensive). >> 300 is two times as expensive as 150, or 100% more expensive than 150 >> >> We know that these don't work symmetrically; if you have a 50% discount, >> you can't get the original price back by adding 50%, because it's 50% of >> a different number. > > "Expensive" is a dimensional term, like length and time. "Cheap" is in > a different category, like shortness. A 6-inch nail is twice as long > as a 3-inch nail, but one doesn't say the latter is twice as short. Agreed. I prefer to avoid multipliers with inverted dimension terms like that. > But if someone asked for a nail twice as short as this (holding up a > 6-inch nail), you might assume they were a non-native speaker of > English, or you might notice you're almost twice as tall as they are: > ie it's a child. (And it would be polite to offer them a 3-inch > nail. Learning all the categories takes time, and some people might > have slightly different boundaries.) I wouldn't assume that; it's a common usage, even though I consider it wrong :-) A bit like the American habit of saying "I could care less", which also doesn't mean what they mean it to mean :-) > It's pretty obvious that Reco's meaning for cheapness was meant to be > understood as a reciprocal cost and not as a discount. It might be a > legitimate idiom in some parts; who knows. Agreed. And many would consider it a 'legitimate idiom'. I personally consider that from a linguistic and mathematical perspective, it doesn't make sense. > One hears stories of pedants insisting they be paid to carry goods out > of the shop because they were labelled "10x cheaper". No way José. I haven't actually insisted on that, but I've certainly thought it :-) Similarly, one of our local fuel stations has (or had) vouchers that say things like '10c per litre off every litre of fuel' - which also quickly gets into trouble if taken literally :-) Richard
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