Question 525672
Let's say Mike has four types of stamps, with a total of 80 stamps. 
Quantity Eq: a + b +c + d = 80
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He has some 29 cent stamps, some 32 cent stamps, some 3 cent stamps, and some 19 cent stamps. The stamps have a total value of $14.94. 
Value Eq: 29a + 32b + 3c + 19d = 1494 cents
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There are 32 stamps that are worth more than 25 cents
a + b = 32
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Four times the number of 29 cent stamps minus 
twice the number of 3 cent stamps is 6.
4a - 2c  = 6
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How many of each type of stamp does Mike have? 
All I need is the set up matrix equation
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Cheers,
Stan H.
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