#1




Coin weights
Comment: Is is true that in US currency, a pound of dimes, quarters, and halfdollars in any combination is worth $20?

#2




I'm pretty sure a quarter weighs more than 2.5 times a dime, so I'd be exceedingly surprised if this were true.

#3




http://www.usmint.gov/faqs/circulati...rculating_coin
Here is a link with the weight and metal composition of circulating US coins. Someone who is better at math than me could probably figure out the answer to your question using this chart. Thinking about your question also reminded me of http://www.coinflation.com which doesn't list the weights of coins, but does show the metal content value of each US coin, both currently circulating and the older silver (pre1964) coins. Not what you asked, but it does show that every dollar (face amount) in pre1964 dimes, quarters, or half dollars is currently worth almost $10.00. It also shows that nickels currently contain about 8 cents worth of metal, and the older pre1982 cents contain more than 2 cents worth of metal. Gresham's Law, anyone? ETA: clarification 
#4




Quote:
$20 worth of quarters = 80 x 5.670g = 453.6 g $20 worth of halfdollars = 40 x 11.340g = 453.6 g i.e. the fact is correct 
#5




$20 worth of dimes is actually 200 dimes, not 2000. 200 dimes makes your equation work, 2000 dimes would be 10 lbs. 
#6




Quote:
It works for 100 dimes (226.8g) + 20 quarters (113.4g) + 10 halfdollars (113.4g) = $20 (453.6g) but does it work for all possible combinations? Done Enrico 
#7




It will work for all combinations of dimes, quarters and halfdollars, since they are all worth $1 per 22.68g

#8




Caught by the pedantry police after almost two months!

#9




Call me a pedant, but correcting a mathematical error of that magintude goes beyond pedantry! 
#10




OK, but you knew what I meant. And I knew what I meant (honestly). I'm not as bad as Verizon.

#11




Just divide the weight of each coin by the face value and figure out if the weight per cent is equivalent.
Penny 2.500 g/cent Nickel 1.000 g/cent Dime 0.2268 g/cent Quarter 0.2268 g/cent Half dollar 0.2268 g/cent Dollar 0.081 g/cent So any collection of dimes, quarters, and halfdollars will have a value of 4.409 cents per gram. Doesn't work with pennies, nickels, and dollars. 
#12




It works, because back when dimes, quarters, halfdollars, and dollar coins were all silver, they contained their respective face values of silver, so a quarter would weigh 2.5 x what a dime did. The nickelcopper et al. coins in circulation now weigh almost the same as the silver originals. Dollars changed in size back in 1979, when the Susan B. Anthony dollar came out, but I'm sure this weight = value formula would work if you used the nonsilver, but silver dollar sized, Eisenhower dollars from the 1970s.
Once upon a time, cents and 5cent nickel pieces (there was also a 3cent nickel once, in the 1860s) contained their face value in metal, but no longer. Cents haven't been all copper for about 150 years, and since the early 80s, have been a bronze plate over zinc. Cut one in half; they're white inside. FWIW, there are minute weight differences between silver, and coppernickel coins, but you have to have more than $10 in coins before the difference shows up on an ordinary household scale. 
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