Question 1101909
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The question 

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    "How many of each type pf stamp does Sam have?"
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does not make sense in this context.  The question which makes sense is

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    "How many of each type of stamps did Sam sell?"
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I will answer the LAST question.


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  x +   y =  24,     (1)     (counting stamps)
27x + 33y = 684.     (2)     (counting cents)


From (1),  y = 24-x.  Substitute it into (2)


27x + 33*(24-x) = 684,'

27x + 33*24 - 33x = 684

-6x = 684 - 33*24 = -108  ====>  x = {{{(-108)/(-6)}}} = 18.


<U>Answer</U>. 18 stamps by 27 cents and  (24-18) = 6 stamps by 33 cents.


<U>Check</U>.  18*27 + 6*33 = 684.    ! Correct !
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