回复：回复：15 is # of combination of 4 numbers out of 6, 20 is 3 out

来源: 泥佛于 2012-04-12 10:35:28 [档案] [旧帖] [给我悄悄话] 阅读数 : (483 bytes)

回答: 回复：15 is # of combination of 4 numbers out of 6, 20 is 3 out of 由 Kamioka 于 2012-04-12 09:37:45

wow! thanks for the RPECISE explanation after coming back from lunch! you're my honored student!!! -- just kidding :)

q2 is similar idea,琼岛春荫 if you son/daughter grasps the basics explained above, he/she will be able to figure out on his/her own. I'll share my answer once i get to it.

p.s. 20 is to pick 3 out of 6, as we know 1st position is taken.

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• I answered Q2 upstairs, please grade. :) -Kamioka- ♀ (281 bytes) () 04/12/2012 postreply 10:52:55

• and thanks for correcting the 20. -Kamioka- ♀ (0 bytes) () 04/12/2012 postreply 11:03:51

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