185' my way C(2,6)C(2,4)=90
170. i am with you
13. 2-HEIGHT被定义为：X的最大因子2^N 的N, K 和M都是政整数，
问K的2-HEIGHT是否大于M的2-HEIGHT
i). K>M
ii).K/M为一个偶数
[确认]:B
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X的最大因子2^N 的N means x=(2^n)*some other numbers
then k=(2^n)*some other numbers
m=(2^n)*some other numbers
if as B states , k/m=even number , that is 2*some other numbers
the n of K is larger than the n of M
but from A) we can not get any clue
therefore B) is sufficient
16. 714前6的倍数和
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the sum of the multiples of 6 , and all those mulitples are smaller than 714
