(1) She bought $4.40 worth of stamps.
(2) She bought an equal number of $0.15 stamps and $0.29 stamps.
any short cut to get answer is A, besides do all the calculation using trial and error?
[此贴子已经被作者于2005-2-7 2:23:05编辑过]
15x+29y=440
要得出结果440各位数是0, 必须两个(15x和29y)个位都是0, 即:y是10的倍数;这里y只能是10,所以得出结果。
[此贴子已经被作者于2005-2-7 4:14:02编辑过]
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