81. 7692-!-item-!-187;#058&005524 At a certain bakery, each roll costs r cents and each doughnut costs d cents. If Alfredo bought rolls and doughnuts at the bakery, how many cents did he pay for each roll?
(1) Alfredo paid $5.00 for 8 rolls and 6 doughnuts.
(2) Alfredo would have paid $10.00 if he had bought 16 rolls and 12 doughnuts.
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发表于 2014-5-28 14:35:44
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