Question 161166
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Let x = number of .23 stamps
then because Jim purchased a total of 120 stamps
120-x = number of .37 stamps
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We also know that he spent a total of $33.90 therefore:
.23x + .37(120-x) = 33.90
.23x + 44.4 - .37x = 33.90
44.4 - .14x = 33.90
44.4 = .14x + 33.90
10.5 = .14x
75 = x (number of .23 stamps purchased)
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.37 stamps:
120-x = 120-75 = 45 (number of .37 stamps purchased)