## Soni-kay Group Title To use a school copier, a 4- digit code using the digits 0-9 must be entered. If each code cannot begin with the number 0 and there are 81 acceptable codes, what is the probability that someone will randomly select a usable code? 2 years ago 2 years ago

1. satellite73

$$\frac{1}{81}$$??

2. philips13

how many four digit numbers are there?

3. Soni-kay

does not say

4. philips13

number acceptable ---------------- will be the answer total number

5. philips13

sure it does... use four digits, 0 to 9.... how many possible codes are there?

6. Soni-kay

i got one

7. philips13

let's see... 0000 0001 0002 0003 0004 ... 9999 so there are how many possible codes?

8. Soni-kay

when u divide

9. Soni-kay

81/10,000

10. philips13

that looks right to me

11. philips13

probability questions usually boil down to number of good ways / number of all the ways

12. Soni-kay

thank you