PDA

View Full Version : Statistics probability


newjerz00
Mar 4, 2009, 04:33 PM
The access code for a warehouse's security system consists of six digits. The first digit cannot be a 0 and the last digit must be even. How many different codes are available?

galactus
Mar 4, 2009, 04:36 PM
How many digits are there to choose from? 0 to 9. There are 10.

The first one can not be 0, so we have 9 choices for the first.

Assuming repetition is allowed, we then have 10 choices for the second, 10 for the third and

So on. The last number has to be even, so there are 4 choices(2,4,6,8).

Can you put it altogether now? Let me know what you get.

newjerz00
Mar 4, 2009, 04:41 PM
Right, okay, but what can I use as the formula?

Six digits total... so I have 9 choices for the first...
10 for the 2nd...
10 for the 3rd..
10 for the 4th...
10 for the 5th and
4 for the 6th...

Can I just multiply them all together?

galactus
Mar 4, 2009, 04:43 PM
Yep, that's what to do.

newjerz00
Mar 4, 2009, 04:49 PM
okay,
I have the answer in the back of my book I just really want to figure out the steps to do it.. and you helped a lot thank you

but the answer they give me is 450,000

and 9x10x10x10x10x4 only equals 360,000

galactus
Mar 4, 2009, 05:08 PM
They're counting 0 as an even number. Make 5 as the last choice instead of 4.

newjerz00
Mar 4, 2009, 05:18 PM
thanks =]