Maths
posted by bubbie .
A locker combination has four nonzero digits. If no digit can be repeated and the first three digits are 123, what is the probability that the fourth digit is 4?
A. 1/6
B. 1/7
C. 1/8
D. 1/9

Maths 
bubbie
i am confused about this problem and would like some help. thank you x.x

Maths 
Ms. Sue
Since the combination has already used 1, 2, and 3. Then the 4th digit must be either 4, 5, 6, 7, 8, or 9.
So the probability must 1 out of 6 or 1/6. 
Maths 
bubbie
thank you, ms. sue! that's what i thought it was but i was confused. :)

Maths (incomplete) 
PsyDAG
With your data, I am confused too. How many total numbers are there?
Since the first 3 numbers cannot be repeated, the answer = 1/(total3) 
Maths 
Ms. Sue
You're welcome, bubbie.

Maths 
bubbie
nonzero digits = 19
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