选了C，考虑了头朝上或头朝下的情况，所以乘以2。请问为什么这样不对呢？题目只说朝一个方向，没说朝哪边啊

选了C，考虑了头朝上或头朝下的情况，所以乘以2。请问为什么这样不对呢？题目只说朝一个方向，没说朝哪边啊

之前老师的解答没听懂，5辆车不是随便排列吗，为什么要先固定红色

there r 5cars to be displayed in 5 parking spaces with all the cars facing the same direction,of the 5 cars,3 r red,1 is blue,1 is yellow,if the cars are identical except for color,how many different display arrangements of the 5 cars are possible? .20 .25 .40 .60 .125 老师，完全没有思路。