JXX = 6/16*10/15*9/14,
XJX = 10/16*6/15*9/14,
XXJ = 10/16*9/15*6/14,
JXX=XJX=XXJ = 9/56
加起来就是 27/56.
JXX = 6/16*10/15*9/14,
XJX = 10/16*6/15*9/14,
XXJ = 10/16*9/15*6/14,
JXX=XJX=XXJ = 9/56
加起来就是 27/56.
• 对, 3种排列=亲妈组合~ -WISEBAO- ♀ (0 bytes) () 07/27/2016 postreply 10:20:19
• 好好包馄饨,好好学数学,争取当亲妈. -窈窈- ♀ (0 bytes) () 07/27/2016 postreply 10:21:32
• 和娃说的时候,我题目都没读明白.还不知第二种情况是第一口荠菜一定.我口头表达有误,娃也没看出来. -窈窈- ♀ (0 bytes) () 07/27/2016 postreply 10:36:26