Anyone good at math?

[ChezCheese:)]

OK, I'm trying to figure out what one factor I can multiply a price given in euros per kg to arrive at the US dollar price per pound. Not doing the exchange and weight translation separately, but one factor I can multiply, say, €3.95 by to get the dollar cost per pound. Let's say for example the exchange rate is €1=$1.14. Now what?

 

[DaveMatthews]

How about this...

https://www.vcalc.com/wiki/pro/US-Dollars-per-Pound-from-Euros-per-Kilo

 

[twy]

1 Euro = 1.14 dollar
1 kg = 2.20462262 pounds

1 Euro/kg * 1kg/2.20462262lb = 0.45359237 Euro/lb

0.45359237 Euro/lb * $1.14/Euro = $0.52/lb

Euro/kg to $/lb multiply by 0.517095302

3.95 Euro/kg = $2.04/lb

Basically: Euro/kg * kg/lb * $/euro = $/lb

I do not vouch for the accuracy of this calculation............

Better yet, use the link.

 

[ChezCheese:)]

OK, so if I multiply any per kilo euro price by .517, then I should get the dollar price per pound (presuming the exchange is 1.14 per euro)?

So if I wanted to not worry about a few pennies this way or that, I could say multiply by .5? (or divide in half, obviously). Is this correct? So if I saw peaches for €4.50 a kilo, that would be roughly $2.25 a pound?

€4.50/kg x .517 = $2.33/lb

Yes, close enough.

 

[ChezCheese:)]

Now how would I do that backwards? Say I'm looking at peaches in the US for 4.50/lb. How do I get the rough per kg euro price? Double it I guess, yes?

 

[dodgeman]

I think the formula is e=mc²

 

[Jeremy McCreary]

Now how would I do that backwards? Say I'm looking at peaches in the US for 4.50/lb. How do I get the rough per kg euro price? Double it I guess, yes?

Yes, just take the reciprocal of the conversion factor (or your approximation of it) to go the other way. So ½ goes to 2.

Many can double or halve numbers in their heads, so rounding this conversion from 0.517 to 0.5 = ½ is a reasonable way to convert without touching your phone.

The relative error is only -0.17/5.17 = -0.033 or about -3%, where the minus sign indicates that you've rounded down. And the error going the other way is roughly +3%. Surely close enough for most purposes.