Eight people are to make photo, four of them being standing in the first raw and four of them in the second. Every man standing in the first raw should be lower than that standing exactly behind him, and all people from the same raw should be arranged in order of height increase from left to right. Providing the restrictions mentioned above how many different photo could be taken.
(a) 8
(b)10
(c)12
(d)14
(e)16
[spoiler]AO D. Coul smb explain?[/spoiler]
(a) 8
(b)10
(c)12
(d)14
(e)16
[spoiler]AO D. Coul smb explain?[/spoiler]
