Maths people please help!

Delta Kilo

I cant understand an A part to a probability question and it is really wrecking my head at this stage. I find probability and statistics fairly easy and can do all parts of most questions but this one is really getting to me!

Its 2006 Q7. part (a)
The password for a mobile phone consists of five digits.
How many passwords are possible?
The correct solution is 10*10*10*10*10 = 100,000.
Why is it 10? 10 is 5c2 but why can each digit be chosen twice?

Thomas_S_Hunterson

In the decimal system, each digit in the password can be one of 10 possible 'symbols' i.e. 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

There are 5 digits in th password ergo 10*10*10*10*10

QueenOfLeon

Delta Kilo wrote: »

I cant understand an A part to a probability question and it is really wrecking my head at this stage. I find probability and statistics fairly easy and can do all parts of most questions but this one is really getting to me!

Its 2006 Q7. part (a)
The password for a mobile phone consists of five digits.
How many passwords are possible?
The correct solution is 10*10*10*10*10 = 100,000.
Why is it 10? 10 is 5c2 but why can each digit be chosen twice?

There are 10 digits on a mobile phone - 0-9. Each time you pick a digit for a password, you have 10 possible choices...therefore 10*10*10*10*10

hope that explains it ok

thebigcheese22

Delta Kilo wrote: »

I cant understand an A part to a probability question and it is really wrecking my head at this stage. I find probability and statistics fairly easy and can do all parts of most questions but this one is really getting to me!

Its 2006 Q7. part (a)
The password for a mobile phone consists of five digits.
How many passwords are possible?
The correct solution is 10*10*10*10*10 = 100,000.
Why is it 10? 10 is 5c2 but why can each digit be chosen twice?

I think the fact its 5 c 2 i just a coincidence... Its 10 to the power of 5 because you can pick 10 numbers each time, theres not a restriction on any of the numbers or its order...
Hope that helps, haven't done probability since last year!

QueenOfLeon

dammit sean you got in there before me

Delta Kilo

Anne-Marie!! wrote: »

There are 10 digits on a mobile phone - 0-9.

I'm an idiot. Sorry. I get it now. Jesus i thought i could think better than that but all that is in my head now is the german bildegeschichtes and irish!

Thanks everyone for your replies!