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A pre-1982 penny has a mass of 3.1 grams and a post 1982 penny has a mass of 2.5 grams How many pennies of each type are there if the mass of 20 of them is 61.16 grams?
Wiki User
∙ 14y ago
x + y = 20
3.1x + 2.5y = 61.16
so from the first equation move the y to the other side
x = -y + 20
Substitute into the second equation
3.1(-y + 20) + 2.5y = 61.16
-3.1y + 62 + 2.5y = 61.16
-.6y = -.84
y = 14
so x will be 6
Wiki User
∙ 14y ago
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Is the ratio of copper to zinc in the pennies made after 1982 higher or lower than the ratio of copper to zinc in the pennies made before 1982?
The pre-1982 pennies are 95% copper and 5% zinc. Post-1982 cents are 97.5% zinc and 2.5% copper.
What mineral or rock is in a penny?
A penny is made up of 2.5% copper the rest is sodium and florite Nope, current pennies (from 1982 through 2010) are copper clad zinc. Starting in 2011 the mint is debating several options from discontinuation to changing to use of a special steel alloy that is "copper colored". Before 1982, pennies were bronze alloys of various types. Sodium and fluorine could not be use in coins!
What pertentages of copper and zinc are in pennies?
Lincoln cents from 1982 to date are 99.2% Zinc & 0.8% copper.
How do you tell the difference between a copper penny and a copper-plated zinc penny?
Well, there are two ways. You could scratch it or melt it over a flame to check composition. Or, you could check the date. The first US penny was minted in 1793 and was 100% pure copper. In 1856 the cent's size was reduced and they were changed to an alloy that was 88% copper and 12% nickel, although pure copper large cents continued to be produced as well for one more year. The nickel alloy was hard to strike and the coins had a whitish appearance so in 1864 a bronze alloy of 95% copper and 5% tin and/or zinc was adopted. In 1943 the US made the famous steel pennies. These were made for only one year and were zinc coated steel. There was a copper shortage because of the war. There were a few copper pennies made that year also and they are now quite valuable. Bronze pennies were resumed in 1944. In 1962 the US stopped using tin pennies and they became just 95% copper and 5% zinc. In the middle of 1982 the price of copper rose to the point where each penny contained more than 1¢ worth of metal. The composition was changed again to copper-plated zinc (97.5% zinc and 2.5% copper.) So, unless you have a US large cent it is in some way less than 100% pure copper. For more information about US coins the US mint is the place to get answers. www.USMint.gov Anne Boiled Down If it's dated 1982 or older, then it's copper ... If it's dated 1983 or newer, then it's zinc with a thin copper plate ... If it's 1982, weigh it -- if it's 3.1 grams then it's copper .. if it's 2.5 grams then it's zinc. Unless it is one of the few mistakes the U.S. made in 1983 when they made about 100 copper pennies that are very rare and expensive today.
Copper in penny?
Assuming that you are asking about US Lincoln cents: If they are dated 1909-1982 (except 1943-46) - they are 95% copper and 5% zinc (with a tiny amount of tin up through 1962) and weigh 3.089 grams (147 to the pound) - 3.25g of copper per. If they are dated 1982-onward - they are 2.5% copper and 97.5% zinc and weigh 2.500 grams (181 to the pound) - 0.0625g of copper per. If they are dated 1982 - its tough to tell, because both types were minted. If they are dated 1943 - they are made of zinc coated steel and contain no copper If they are dated 1944-1946 - they are made from old brass shell casings (I'm not sure of the copper content, but likely similar to other pre-1982 cents).
Which is more dense a pre 1982 penny or a post?
8.869 grams per cubic centimeter approximately. Some 1982 pennies are made of bronze alloy (pre1982) and some are copper plated zinc (post 1982). The change was made at the beginning of 1982 after some pennies had already been struck.
Why does a 1982 penny weigh more than a 2006 penny?
In 1982 the mint struck pennies from solid bronze and from copper-plated zinc. Bronze cents weigh 3.1 grams and the zinc once weigh 2.5 grams. Bronze pennies were discontinued in mid-1982
How much does a copper penny weight?
Pre-1982 copper pennies weigh 3.11 grams. Pennies made since then are mostly zinc and weigh 2.5 grams.
How much does copper penny weigh?
Copper pennies minted before 1982 weigh 3.11 grams.
What makes the pennies from the 1980's different from todays pennies?
In 1982 the US mint changed the composition of the penny from mostly copper to zinc which changed the weight form 3.11 grams to 2.5 grams and made the penny cheaper to make.
What objects weigh 3 grams?
The one cent piece, or penny, weighs about 3 grams. Pennies made between 1944 and 1982 weigh 3.11 grams while pennies made afterwards weigh 2.8 grams.
How much does 10000000 pennies weigh?
A single penny (after 1982) weighs 2.5 grams, so 10,000,000 pennies would weigh 25,000,000 grams, 55,115.5655 pounds, or 27.5577827 short tons.
How much would 3000 pennies weigh?
The Lincoln, Wheat Ears Reverse penny weighs 3.11 grams. The Lincoln, Memorial Reverse penny (1959 to 1982) weighs 3.11 grams. The Lincoln, Memorial Reverse penny (1982 to present) weighs 2.5 grams. So it would all depend on which year the penny was minted.
One hundred pounds of pennies is how many dollars?
* There are 453.5923696 grams per pound. * A post-1982 penny weighs 2.5 grams. Therefore, there are = 181.44 pennies per pound Multiplied by $100: $181.44
How can you tell if a 1914 d penny is a replica?
Check the weight. Copper pennies (pre-1982) should weigh 3.11 grams.
How much copper is in a wheat penny?
Pennies minted before 1982, which includes all wheat pennies (except in 1943) contain 95% copper and weigh 3.11 grams.
How much does a 1982 D penny weigh?
1982 is the year the composition was changed from copper to zinc. The copper version weighs 3.1 grams, and the zinc version weighs 2.5 grams.
