@Esnart Banda
how many nine digits numbers can be obtaind by using each of the nine digits exacty once?
9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 362880 numbers
how many of these are greater than five million(5,000,000) ( 7 digits)?
7! = 5040 numbers have 7 digits
362880 - 5040 = 357840 numbers are greater than 5 million.
I am not sure about the correctness of the answer…but this is what i could think of…do post the correct answer if you find it…
Abhi n neetu park their cars in an empty parking lot with n>=2 consecutive parking spaces (I.e n spaces in a row where only one car fits in each space) abhi n neetu pick parking spaces at random.all pairs of parking spaces. Are equally likely.what is the probability that there is at most one empty parking spaces between them???
hey,. please help me with this question :
A witness told the police that the plat number contained the letters P,D,W followed by 3 digits, the first of which is 5. If the witness cannot recall the last 2 digits, but is certain that all 3 digits are different, find the number of car registration that the police may have to check.
Thank you so much 
its my first time on this site and i thank God for the oppotunity. been struggling with ths question for hours. please help me out:
how many nine digits numbers can be obtaind by using each of the nine digits exacty once?
how many of these are greater than five million?
Thanks lot for better explanation.
wasnt helpful
When can the number if permutations and combinations of n objects taken r at a time be equal?
hi sir, u r really outstanding,plz give some more basic solutions for the bignrs to pick it easily.
a problem from biology: How many different possibilities are there to make a 100 amino acid long protein (there are 20 different amino acids, and they can be arranged in any order and can occur in any frequency). I assume it would be 20^100. This is neither a permutation nor combination. Is there a mathematical name for it?
Thanks
Great website, BTW!
Thanks Eric! In a way, you can think of this as a sequence of 100 combinations: you have 20 choices, then 20 choices, then 20 choices, etc. So it’s really (20 choose 1) taken over and over again :).
how do i map a word problem into one involving permutation and combination?
e.g. if i have N slots to fill with a combination of size 1 and / or 2. Here, the order matters. e.g for N=5, 1+1+1+2 = 5 v/s 2+1+2 = 5 are different permutations.
i) In how many ways can an escort. of four solders be choosen from nine solders?
ii)In how many of these escort will a particular soldier be included?
Thanks a lot … I have a maths test just after 4 hours and and I finally know what this actually is !
Answers to the above Question…:
1-33033000
2-86400
3-288
I don’t understand this problem could you help?
The instruction booklet for MM actually contains a chart showing how many possible codes there are, for any number of colors form 1 to 7, and allowing or disallowing repeated colors. Explain how you would go about making such a table. (You don’t have to calculate all of the values.) What will be the smallest an largest values in the table?
Hi, my name is Monique:-)
This is really cool… Pretty much easier to understand… Thanks alot… Awesome!!!
What a great explanation!
Finally I got it… Thankx a lot
Just so things are clear for me,
Can I also say that of the 8! ways we can arrange 8 objects, (8-3)!
of them will start off with the same ordered triplet of objects
and the rest of the objects will arrange itself it (8-3)! different ways
and this is why we divide 8! with (8-3)! when finding the number of ordered
triplets in a list of 8 objects.
Is this a good way to explain it to myself or am I thinking about this wrong?
I’d also like to mention that I am truly grateful for
all of this mathematical clarification you offer to the public
for no charge