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. Richard
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