Question 188530
leslie buys 38 stamps for 9.88. If each stamp cost either 32 cents or 20 cents how much of each kind can she buy 
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let the 32 cents be "a" stamps
let the 20 cents be "b" stamps
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Equations:
Quantity Eq. : a + b = 38
Value Eq.....:32a+20b= 988 cents
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Modify to set the system for elimination:
20a + 20b = 20*38
32a + 20b = 988
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Subtract the 1st from the 2nd to solve for "a":
12a = 988 - 760
12a = 228
a = 12 (# of 32 cent stamps)
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Substitute to solve for "b":
12 + b = 38
b = 24 (# of 20 cent stamps)
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Cheers,
Stan H.