please help this stupid head!

hollandgirl · 发表于 2006-10-13 23:56:00

Q19:

How many 4-digit positive integers are there in which all 4 digits are even?

A. 625

B. 600

C. 500

D. 400

E. 256

my choice is A,but the answer given is C, I am confused.help me!

[此贴子已经被作者于2006-10-14 0:05:57编辑过]

magileilei · 发表于 2006-10-14 00:16:00

对的呀,千位数字可以是2,4,6,8 个/十/百位数可以是0,2,4,6,8

c(4,1)*c(5,1)*c(5,1)*c(5,1)=500

hollandgirl · 发表于 2006-10-14 01:26:00

谢谢！

所属分类: GMAT考试