There are 140 stamps which are 3-cent stamps and 4-cent stamps. Altogether they cost 490 cents. How many 3-cent stamps are there?
There are 210 stamps which are 3-cent stamps and 5-cent stamps. Altogether they cost 850 cents. How many 3-cent stamps are there?
There are 240 stamps which are 3-cent stamps and 9-cent stamps. Altogether they cost 1380 cents. How many 3-cent stamps are there?
There are 230 stamps which are 6-cent stamps and 5-cent stamps. Altogether they cost 1260 cents. How many 6-cent stamps are there?
There are 280 stamps which are 4-cent stamps and 3-cent stamps. Altogether they cost 990 cents. How many 4-cent stamps are there?
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There are 150 stamps which are 7-cent stamps and 3-cent stamps. Altogether they cost 770 cents. How many 7-cent stamps are there?
There are 220 stamps which are 4-cent stamps and 8-cent stamps. Altogether they cost 1200 cents. How many 4-cent stamps are there?
There are 180 stamps which are 3-cent stamps and 7-cent stamps. Altogether they cost 780 cents. How many 3-cent stamps are there?
There are 200 stamps which are 7-cent stamps and 6-cent stamps. Altogether they cost 1300 cents. How many 7-cent stamps are there?
There are 120 stamps which are 6-cent stamps and 4-cent stamps. Altogether they cost 620 cents. How many 6-cent stamps are there?
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