0
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
Let x be the number of pre-1982 pennies and y be the number of post-1982 pennies. You can create a system of two equations based on the information given: 3.1x + 2.5y = 61.16 (total mass equation) x + y = 20 (total number of pennies) From there, you can solve for x and y to find out how many of each type of penny there are.
Add your answer:
Earn +20 pts
Does pennies have iron in it?
Yes, pennies minted after 1982 in the United States are made of copper-plated zinc, not iron. However, older pennies minted before 1982 are made of 95% copper.
Which pennies are magnetic?
It depends on which country we are talking about. For the US, there is only one magnetic coin the 1943 steel penny. For Canada, there have been some magnetic pennies made since 2000, though there were zinc pennies made until 2008. For the UK, pennies have been magnetic (copper plated steel) since 1992.
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.
Are there any valuable copper US pennies and if so what years?
Yes, there are valuable copper US pennies, typically those that are made of mostly copper and are older. Pre-1982 pennies are mostly copper (95% copper, 5% zinc), making them more valuable than post-1982 pennies which are mostly zinc. Some valuable copper pennies include the 1943 copper penny, 1909-S VDB, and 1955 doubled die penny.
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!
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.
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 1 in US pennies weigh?
3.11 grams for pennies made from 1959 to 1982
How much does copper penny weigh?
Copper pennies minted before 1982 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.
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 does 2000 pennies weight?
A pre-decimal British Penny - (to 1967) weighs 9.45 grams. A British Penny - (1968 - 1991) weighs 3.56 grams. A British Penny - (1992 to present) weighs 3.56 grams. An Australian Penny - (1911 to 1964) weighs 9.45 grams. An New Zealand Penny - (1940 to 1964) weighs 9.45 grams. A US 1 cent (Penny) - (to 1982) weighs 3.11 grams. A US 1 cent (Penny) - (1982 to present) weighs 2.5 grams. Select one and multiply by 2,000.
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.
Why does a 1982 penny weigh more than a 2006 penny?
The 1982 penny is made of 95% copper and 5% zinc, while the 2006 penny is made of 97.5% zinc and 2.5% copper with a thin coating of copper. Copper is denser and heavier than zinc, which accounts for the weight difference between the two pennies.
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 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.
