Explore BrainMass

Probability : Counting Principle

Not what you're looking for? Search our solutions OR ask your own Custom question.

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

A social security number has 9 digits. How many different S.S numbers are possible if:

a. repetition of digits is permitted
b. repetition of digits is not permitted
c. the first digit cannot be a 0 and repetition is not permitted

I need the layout (counting principle)
ex. 9 8 7 - 6 5 - 2 1 4 3
- - - - - - - - -
Thankyou

I think the answer for a= 1,000,000,000
for b= 3,628, 800 and for c= 3,265,920
Let me know!

https://brainmass.com/math/probability/probability-counting-principle-10168

Solution Preview

It's a counting problem. Follow the condition carefully and you won't miss it.

Please see the attached file for the complete solution.
Thanks for using BrainMass.

A social security number has 9 digits. How many different S.S numbers are possible if:

a. repetition of digits is permitted
b. repetition of digits is not permitted
c. the first digit cannot be a 0 and repetition is not permitted

I need the layout(counting principle)
ex. 9 8 7 - 6 5 - 2 1 4 3
- - - - - - - - -
Thankyou

I think the answer for a= 1,000,000,000
for b= 3,628, 800 and for c= ...

Solution Summary

Counting problems are solved and explained.

\$2.49