600  Stamp
How many stamps? 1

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There are 210 stamps which are 7-cent stamps and 4-cent stamps. Altogether they cost 1230 cents. How many 7-cent stamps are there?



There are 200 stamps which are 3-cent stamps and 7-cent stamps. Altogether they cost 1000 cents. How many 3-cent stamps are there?



There are 210 stamps which are 7-cent stamps and 4-cent stamps. Altogether they cost 1260 cents. How many 7-cent stamps are there?



There are 180 stamps which are 8-cent stamps and 4-cent stamps. Altogether they cost 1080 cents. How many 8-cent stamps are there?



There are 170 stamps which are 7-cent stamps and 6-cent stamps. Altogether they cost 1120 cents. How many 7-cent stamps are there?



There are 220 stamps which are 3-cent stamps and 7-cent stamps. Altogether they cost 1100 cents. How many 3-cent stamps are there?



There are 230 stamps which are 6-cent stamps and 3-cent stamps. Altogether they cost 1140 cents. How many 6-cent stamps are there?



There are 210 stamps which are 7-cent stamps and 9-cent stamps. Altogether they cost 1690 cents. How many 7-cent stamps are there?



There are 220 stamps which are 6-cent stamps and 5-cent stamps. Altogether they cost 1190 cents. How many 6-cent stamps are there?



There are 250 stamps which are 7-cent stamps and 4-cent stamps. Altogether they cost 1360 cents. How many 7-cent stamps are there?



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600    130 100 140 90 100 ( 560 )   110 150 100 90 120 ( 570 )   [[ 1130 ]]