If there are 4 tellers working at a bank, and they add a 5th, which (if any statement) is right?
there are 20% more tellers (5/4 = 1.2 = 120%)
there are 25% more tellers (1 new/4 old = .25 = 25%)
You are comparing apples and oranges, there are 25% MORE tellers, or 120% AS MANY. I suppose it’s just the way you want to quantify it.
Mortimer
Better check your math. 5/4 is 1.25, or 125%. No matter how you put it, the number of tellers increased by 25%. However, if you then fire the 5th teller, you now have 20% fewer tellers, not 25%. (4/5=0.80=80%).
Applied problem: sales tax in your area is 10%. One store is having a 10% off sale (10% off untaxed price, then 10% of the sale price added as tax). Another store is having a “no sales tax” sale. Which store should you shop at?
I’m with scr4. The 5/4 = 120% thing is a good point, but all it means is that, after all is said and done, 20% of the staff are new hires.
You could run into some real problems if you weren’t paying attention. Say, in a fat year the budget allowed a 100% increase in staff. Then, in a lean year, you were forced to reverse your staffing changes … by making a 100% decrease in staff? No, stick with a 50% decrease.
One situation in which the question is really ambiguous is when comparing two “simultaneous” numbers. Say Joe estimates that the Funk Operations Branch will bring in $100,000 in net profits. Millie estimates it will bring in $150,000. Do their estimates differ by 33%, or by 50%? I asked a chem teacher this once, and she said to use the one you think is right as the denominator. Which was about as helpful as a lash with a wet noodle.
Illiteracy with percentages in the media is one of my pet peeves. They love big numbers so if a figure increased by a factor of 30 they will say it increased by 3000% which is wrong, the correct number is 2900%. IMHO percentages should only be used with small numbers, up to, say, 100%. It is better to use the factor for greater numbers.
I also love it when they say things like “sales decreased by 250%” (what?) We all know reporters are illiterate and don’t have a clue of what they are talking about but this is a bit much.
But to get to the question at hand. There is no doubt or ambiguity. If I have 4 people in the house and one of them gives birth, the population has increased by 25%. If a house has 5 people an one dies, the population has decreased by 20%. I cannot understand the doubt.
the other question: if a store offers a 10% discount a $100 item sells for $90 plus 10% tax= $99
If they offer to pay the tax, I pay $100
I hate mail-in rebates for many reasons but one of them is that it is a really stupid way of wasting money that goes to third parties for no good reason. If a $100 item has a $30 mail-in rebate, I still pay tax on those $30 even though the actual price paid is not the full $100 but $70.
In general I am not for legal regulation of commerce but mail-in rebates are so close to being a scam that I would regulate them closely. How about a law that said something like: “If a mail-in rebate is offered, the vendor is obligated to advance the rebate on the spot and is authorised to subrogate and collect from the manufacturer who offered the rebate” That way the hassle of collecting the rebate falls on the store.
OOps, sorry, didn’t mean to hijacj the thread…