A) \[5\ !\]
B) \[2(5\ !)\]
C) \[10\ !\]
D) \[\frac{1}{2}(10\ !)\]
Correct Answer: D
Solution :
Without any restriction the 10 persons can be ranked among themselves in \[10\ !\] ways; but the number of ways in which \[{{A}_{1}}\] is above \[{{A}_{10}}\] and the number of ways in which \[{{A}_{10}}\] is above \[{{A}_{1}}\] make up\[10\ !\]. Also the number of ways in which \[{{A}_{1}}\] is above \[{{A}_{10}}\] is exactly same as the number of ways in which \[{{A}_{10}}\] is above\[{{A}_{1}}\]. Therefore the required number of ways\[=\frac{1}{2}(10\ !)\].
You need to login to perform this action.
You will be redirected in
3 sec
