Q: How many strings with seven or more characters can be formed from the letters in EVERGREEN?
What am I suppose to do for this question? Since it asks for "seven or more", am i suppose to add up all the different possibilities?
My answerim not sure if its right)
[ (7!/(2!2!)) + (7!/(4!)) + (7!/(3!)) ]- For this i took out 2 E's, then 2 R's, then E and R
[ (8!/(3!2!)) + (8!/(4!)) ]- For this i took out 1 E, then 1 R.
Is that the correct answer? If not please correct me.
This is not a hard problem but it is very time consuming.
Just to find the number of seven strings there are many cases.
[EEEERRN]; [EEEERRG]; [EEEERRV]; [EEEERGN]; [EEEERVN];
[EEEERVG]; [EEEEVGN]; [EEERVGN]; [EERRVGN].
Now count each of those cases (If I have not missed some!)
Do the same thing for an eight string.
The nine string is the easy case (why?)