SOLUTION: While gerald was at the post office he purchased some 40 cent stamps and three times as many 30 cent stamps. in all the stamps cost $20.80. how many of each did he buy

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Question 1030658: While gerald was at the post office he purchased some 40 cent stamps and three times as many 30 cent stamps. in all the stamps cost $20.80. how many of each did he buy
Answer by CubeyThePenguin(3113) About Me  (Show Source):
You can put this solution on YOUR website!
x = number of 30 cent stamps
y = number of 40 cent stamps

x = 3y
30x + 40y = 2080

Use substitution.

30(3y) + 40y = 2080
130y = 2080
y = 16

Gerald bought 48 30-cent stamps and 16 40-cent stamps.