a*****g
发帖数: 1320 | 1 【 以下文字转载自 SanFrancisco 讨论区 】
发信人: ashuang (不要迷恋哥，哥只是个传说), 信区: SanFrancisco
标 题: 一道 中学数学题求助
发信站: BBS 未名空间站 (Sun Nov 7 12:42:22 2010, 美东)
麻烦给出解题过程， 谢谢了。
THE PRODUCT OF THE DIGITS OF 3214 IS 24. HOW MANY DISTINCT FOUR-DIGIT
POSITIVE INTEGERS ARE SUCH THAT THE PRODUCT OF THEIR DIGITS EQUALS 12? (TWO
EXAMPLES TO INCLUDE ARE 1126, 6112)
A. 33 INTEGERS B. 34 INTEGERS C. 35 INTEGERS D.36 INTERGERS. | B***i
发帖数: 724 | 2 12 = 1 * 2 * 2 * 3 = 1* 1 * 3 * 4 = 1 * 1 * 2 * 6
1,2,2,3 has 12 combination
1,1,3,4 has 12 combination
1,1,2,6 has 12 combination,
total 36 | a*****g
发帖数: 1320 | 3 Thanks a lot!
【在 B***i 的大作中提到】
: 12 = 1 * 2 * 2 * 3 = 1* 1 * 3 * 4 = 1 * 1 * 2 * 6
: 1,2,2,3 has 12 combination
: 1,1,3,4 has 12 combination
: 1,1,2,6 has 12 combination,
: total 36
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