由数字1,2,3,4,5,6任取若干个相加,和为偶数的取法有多少种
由数字1,2,3,4,5,6任取若干个相加,和为偶数的取法有多少种
答案为31种
答案为31种
数学人气:487 ℃时间:2019-11-15 06:21:53
优质解答
不同个数的数的取法有,(1)取一个数和为偶数的取法:n1=C(3,1)=3种(三偶任取其一)(1)取两个数和为偶数的取法:n2=C(3,2) + C(3,2)=6种(两奇或两偶)(2)取三个数和为偶数的取法:n3=C(3,2)*C(3,1)+ C(3,3.)=1...
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