gwd10-36

lingdang1988

Each signal that a certain ship can make is comprised of 3 different flags hanging vertically in a particular order. How many unique signals can be made by using 4 different flags?
A. 10
B. 12
C. 20
D. 24
E. 36

lingdang1988

偶笨啦，谢谢！！！[em07]

creativity

此题，从4面旗子里面选3面排列就好啦~

P43=4*3*2=24...还真不是一般的简单~LZ是题目没看懂吗？？