Permutations/Combinations/Multiplication rule

[JimmysJohnson]

G'day im currently taking an intro to prob course and although i can grasp the statistics side of things such as distributions, i simply cannot understand the basics. Although i may have trouble with some topics in chemistry, physics or calc, with a bit of work i always understand it, this doesn't seem to be the case. I may see the answer and on the odd occasion see the reasoning behind it, but i am never able to apply that to other questions. Can you guys perhaps provide any insight to how you think about these questions or the reasoning behind it or how i might be able to learn?
e.g.
Imagine we randomly generate 6 digit number from the digits 0 through 9,
A) What is probability of getting 999,999
The answer to A is meant to be 10^-6, I have no idea how i would approach it

 

[Cubist]

Hi, welcome to the forum. Probability questions can be quite mind boggling. Sometimes you can get an insight into a problem by simplifying it, ie think about an equivalent question with 1 or 2 digits.

EDIT: When I say "equivalent question" I mean "equivalent type of question". So the answer will be different, but it might give you a clue about how to go about solving the original.

Back to your specific question...

Imagine we randomly generate 6 digit number from the digits 0 through 9,

A1) How many different six digit numbers are possible?

What is probability of getting 999,999

A2) How many of the possible six digit numbers match this criteria?

--

Then divide A2 by A1

 

[Deleted member 4993]

G'day im currently taking an intro to prob course and although i can grasp the statistics side of things such as distributions, i simply cannot understand the basics. Although i may have trouble with some topics in chemistry, physics or calc, with a bit of work i always understand it, this doesn't seem to be the case. I may see the answer and on the odd occasion see the reasoning behind it, but i am never able to apply that to other questions. Can you guys perhaps provide any insight to how you think about these questions or the reasoning behind it or how i might be able to learn?
e.g.
Imagine we randomly generate 6 digit number from the digits 0 through 9,
A) What is probability of getting 999,999
The answer to A is meant to be 10^-6, I have no idea how i would approach it

There are 10 numbers - 0 through 9.

What is the probability that you will choose '9' (out of the available 10 numbers) for seat 1?