A 4-digit code is needed to unlock a bicycle lock. The digits 0 through 9 can be used only once in the code. What is the probability that all of the digits are even?

Question

highschoolmom2010 · Answer

its permutation here correct?

ganeshie8 · Answer

correct

anonymous · Answer

You can solve the problem in terms of permutations. You would find the number of permutations of even digits, and divide by the number of permutations of any digits.

anonymous · Answer

Alternatively, just realize that each digit has a one-half chance of being even, and you need to get 4 even digits. So, the probability would be $$\left(\frac{1}{2}\right)^4$$

highschoolmom2010 · Answer

what.....

anonymous · Answer

I'm sorry, I misread the problem. Disregard that last answer - permutations are the way to go.

perl · Answer

I got 
5*4*3*2 / ( 10*9*8*7)

perl · Answer

because the question said, digits do not repeat

highschoolmom2010 · Answer

so how would i need to set up the  nPr  formula that is where i got lost at.....

highschoolmom2010 · Answer

@ganeshie8  @perl @srossd