Out of 10 persons


Out of 10 persons P1P2,..., P10, 5 persons are to be arranged in a line such that in each arrangement P1 must occur whereas P4 and P5 do not occur. The number of such arrangements is ___________.


Since out of 5 to be selected, P1 is fix i.e P1 must occur.

⇒ we need to select 4 person out of 9 remaining.

Now, out of remaining 9, P4 and P5 do not occur 

⇒ Available options are 7

⇒ Number of such arrangement  

7C4 ×  5!   (since 5 persons in line can be arranged in 5! ways.) 

Leave a comment


Click here to get exam-ready with eSaral

For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.

Download Now