simple perms n combs question. (1 Viewer)

[conics2008]

hey just incase a question comes up in the form of perms or combs in the hsc i want to just understand how to do this..

how many 4 letter words can be arranaged from the word DIVERSITY..

ps: in the hsc i wont even bother with prob + perms + combs quesiton unless i find them easy


Thanks in advance

 

[Affinity]

case bash

case 1: atmost 1 I in the word ---> 8*6*7*5
case 2: 2Is in the word -> 7*6 * 4*3
add them together