SOLUTION: if you have a bunch of 10 cent and 5 cent stamps, and you know that there are 20 stamps and their total value is $1.50, how many of each do you have?

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Question 642048: if you have a bunch of 10 cent and 5 cent stamps, and you know that there are 20 stamps and their total value is $1.50, how many of each do you have?
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!

If you have a total of objects of 2 types, let the number of each be referred to as and . Then, if the total value of all of the objects is when the value of each object type 1 is and the value of each object type 2 is , you can write the following two equations:



and



Solve for by elimination:

Multiply the first equation by



Then add the two equations:





Once you know , you can substitute into equation 1 to get a single variable equation in that can be solved by ordinary means.

Note: in your specific problem be careful of your monetary units. The per each values of the stamps are given in cents, whereas the total value is given in dollars. My recommendation for this problem, so as to avoid decimal fraction coefficients, would be to convert $1.50 to 150 cents.

John

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