510  Stamp
How many stamps? 1

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There are 150 stamps which are 7-cent stamps and 3-cent stamps. Altogether they cost 850 cents. How many 7-cent stamps are there?



There are 180 stamps which are 8-cent stamps and 4-cent stamps. Altogether they cost 1040 cents. How many 8-cent stamps are there?



There are 140 stamps which are 4-cent stamps and 7-cent stamps. Altogether they cost 710 cents. How many 4-cent stamps are there?



There are 230 stamps which are 3-cent stamps and 8-cent stamps. Altogether they cost 1190 cents. How many 3-cent stamps are there?



There are 130 stamps which are 8-cent stamps and 3-cent stamps. Altogether they cost 790 cents. How many 8-cent stamps are there?



There are 190 stamps which are 7-cent stamps and 5-cent stamps. Altogether they cost 1210 cents. How many 7-cent stamps are there?



There are 260 stamps which are 7-cent stamps and 9-cent stamps. Altogether they cost 2060 cents. How many 7-cent stamps are there?



There are 160 stamps which are 8-cent stamps and 3-cent stamps. Altogether they cost 980 cents. How many 8-cent stamps are there?



There are 160 stamps which are 7-cent stamps and 5-cent stamps. Altogether they cost 960 cents. How many 7-cent stamps are there?



There are 220 stamps which are 8-cent stamps and 3-cent stamps. Altogether they cost 1110 cents. How many 8-cent stamps are there?



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510    100 80 90 130 80 ( 480 )   130 140 100 80 90 ( 540 )   [[ 1020 ]]