by Madwest » Fri Feb 24, 2012 12:50 am
From an accurate weight, you can know exactly how many Cu and how many Zn there are. It is an exercise of 2 equations with 2 unknowns.
A $50 bag (or 2x boxes) contains 5000 coins. You don't know how many are Cu and how many are Zn. The equation looks like this:
(Cu + Zn) = 5000. Unknown variable "Cu" is the number of copper cents. Unknown variable "Zn" is the number of zinc cents.
The second equation requires you to weigh the coins and the packaging that they are in. The equation then looks like this:
(3.11*Cu + 2.50*Zn) = (Weight - Package). Unknown variables "Cu" and "Zn" have the same meaning as in the first equation. "Weight" is the total weight of your bag/boxes of coins [in grams] and "Package" is the weight of the box+wrappers or coin bag [in grams] that contain them. Remember, coppers weigh 3.11gm and zincs weigh 2.50gm.
I'll skip the mathematics, and go right to the answer.
The number of coppers in your boxes/bag is: Cu = (Weight - Package - 12500)/0.61
Remember:
"Weight" is the total weight in grams.
"Package" is the weight of your box+wrappers (or bag) in grams.
"Cu" is the number of coppers in your box or bag.
For all weights in Kg, the equation is: Cu = (Weight - Package - 12.5)*1639
For all weights in lbs, the equation is: Cu = (Weight - Package - 27.558)*743.6
For a single box, the equation for grams is: Cu = (Weight - Package - 6250)/0.61
For kg, Cu = (Weight - Package - 6.25)*1639
For lbs, Cu = (Weight - Package - 13.78)*743.6