Question 145296
B=# of 37c stamps
L=# of 20c stamps
B+L = 56
37B+20L = 1800
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B=56-L
Substitute for B
37(56-L)+20L=1800
2072-37L+20L=1800
2072-17L=1800
-17L=-272
L=16
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B=56-L
B=40