Question

please help, how many 5 digit numbers can be formed from the digits 1,2,3,4,5,6,7

Answer 1

Can the digits repeat?

Answer 2

no

Answer 3

The first digit can be any of the 7 numbers 1,2,3,4,5,6,7.
Having used up one digit and because we are not allowed to repeat the digit, the second can be any of the six digits left.
The third can be any of the five digits left, etc.
So the number of possibilities are: 7 x 6 x 5 x 4 x 3 = 2520

Answer 4

This is a basic statistic math class
dealing with counting, combinations, and for whatever reason I am stuck on this question

Answer 5

to be honest that was the first answer I had, but was unsure if it was correct

Answer 6

You are correct. If the digits can repeat itself the answer will be 7x7x7x7x7

Answer 7

actually I think I x the 2 and 1 as well

Answer 8

not the 1 but the 2, may I asked why did you take away the 2, because i did not

Answer 9

They are asking for a FIVE digit number:

First digit: 7 possibilities
Second digit: 6 possibilities
Third digit: 5 possibilities
Fourth digit: 4 possibilities
Fifth digit: 3 possibilities

Total possibilities for a FIVE digit number = 7x6x5x4x3

Answer 10

ok, I understand Thank you

Answer 11

Can you assist me with two more questions please? I thank you for your help, I really appreciate it

Answer 12

Let me try one more. My statistics is a bit rusty

Answer 13

I don't know anything about poker, never been to vegas, I don't understand the card game.
Explain how you would find the total number of Five card poker hands? Indicate what this
number would be

Answer 14

I don't know the game either! Just look up online for five card poker and see what they say.

Answer 15

ok, I will try that
what about this question,
how many groups of three can be formed using Tom, John, Mary, Sally and Sue

Answer 16

Do you know the formula for permutations and combinations?

Answer 17

yes

Answer 18

\[\Large ^{n}C _{r} = \frac{ n! }{ r!(n-r)! }\]

Answer 19

I k now that the order is not important in forming groups and is also not important in dealing cards

Answer 20

ok so i would use Combinatorial number nCr=N! /R! (N-R)!

Answer 21

so its n objects taking R at a time

Answer 22

Yes. So in the 5 card poker hand they are asking how many ways 5 cards can be drawn from a deck of 52 cards.
n = 52, r = 5
Plug it into the formula

Answer 23

I understand that part am not getting how many groups of three , my answer was 5

Answer 24

ok so we are going back to the poker

Answer 25

for the poker I had 52C5

Answer 26

In the next question you have 5 people and they are asking how many ways you can select 3 people out of the 5. n = 5, r = 3

Answer 27

so would that be 5*4*3

Answer 28

Yes poker is 52C5 = 52!/(5!47!) = 52x51x50x49x48/(5x4x3x2x1) = ?

Answer 29

5C3 = 5!/(3!2!) = 5x4/2 = 10

Answer 30

ok the 5C3 number of five people, question, so 5!/ (3!2!)5-3=2 where did the 4 come from

Answer 31

we are going back to the question of 5 people and how many ways you can select 3 people out of five

Answer 32

5C3=5!/(3!2!)

Answer 33

\[\Large 5C3 = \frac{ 5! }{ 3!2! } = \frac{ 5\times4\times3\times2\times1 }{ (3\times2\times1)(2\times1)}\]

Answer 34

See how the 3x2x1 in the numerator and the denominator cancel out?

Answer 35

yes

Answer 36

So instead of expanding 5! all the way I knew I can stop it at 5! = 5x4x3! because I see a 3! in the denominator that will cancel it out.

Answer 37

I understand, Thank You!

Answer 38

you are welcome.

Answer 39

How often are you on this site for assistance?

Answer 40

As time permits. But don't be hesitant. Just post the questions in the general area and there are a number of people who would jump in to help you out.

Answer 41

I am taking classes online and I am active duty military, so it is hard to find a math tutor at night.

Answer 42

I have not taken a math class in over 10 years
I really appreciate your help, have a good night

Answer 43

You too.