there are 7*10^3 pin codes
there are 1*10^2*1 of the form 5xx3
so P(5xx3) = 100/7000 = 1/70
A 4-digit pin code can begin with any number except 0,1 & 2. If repetition of the same
digit is allowed, the probability of a pin code begin with 5 and end with a 3 is?
1 answer
5 answers