SOLUTION: Some US one cent coins are made mostly of copper (each has a mass of 3.1 grams). Some US one cent coins are made mostly of zinc (each has a mass of 2.5 grams).
Mr. Kniser has a
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Mr. Kniser has a
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Question 187807: Some US one cent coins are made mostly of copper (each has a mass of 3.1 grams). Some US one cent coins are made mostly of zinc (each has a mass of 2.5 grams).
Mr. Kniser has a bag of 1000 US one cent coins. The total mass of the bag is 2616.4 grams. How many of each type of cent is in the bag? Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! Some US one cent coins are made mostly of copper (each has a mass of 3.1 grams).
Some US one cent coins are made mostly of zinc (each has a mass of 2.5 grams).
Mr. Kniser has a bag of 1000 US one cent coins. The total mass of the bag is 2616.4 grams.
How many of each type of cent is in the bag?
:
Let c = no. of copper coins
Let z = no. of zinc coin
:
A system of two equations:
:
total no. of coins
c + z = 1000
which can be written:
c = (1000-z)
:
and total weight
3.1c + 2.5z = 2616.4
:
Substitute (1000-z) for c in the above equation:
3.1(1000-z) + 2.5z = 2616.4
3100 - 3.1z + 2.5z = 2616.4
-.6z = 2616.4 - 3100
-.6z = -483.6
z =
z = +806 zinc coins
and
1000 - 806 = 194 copper coins
;
:
Check solution in the weight equation
3.1(194) + 2.5(806) =
601.4 + 2015 = 2616.4
