SOLUTION: An office has some 20 cent stamps and some 28 cent stamps. Altogether the office has 140 stamps for a total value of $31.20. How many of each type of stamp does the office have?
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Question 349362: An office has some 20 cent stamps and some 28 cent stamps. Altogether the office has 140 stamps for a total value of $31.20. How many of each type of stamp does the office have?
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
You have a collection of two types of things. You have 
of one type of thing and 
of the other type of thing such that the total number of things you have is a known number 
. The value of the first kind of thing is 
each and the value of the second kind of thing is 
each and you know the total value of both of your things is 
.
You can then say:
and
Giving you a system of linear equations. Solve the system for and using substitution, elimination, or Cramer's rule.
John
My calculator said it, I believe it, that settles it
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