In a 6 digit ID number, what is the probability of exactly four digits are the digit 0?
Select the correct option:
A) 9/2000	B) 81/20000	C) 12/36001	D) 81/16000	E) 84/3600
Total number of 6 digit numbers = 9*10*10*10*10*10 = 9,00,000   No. of ways of arranging 4 digits as 0 = 5C4=5.   Arrangements are as follows. Here X can be any digit other than 0   1) XX000X ==&gt; no. of ways - 729   2) XXX000 ==&gt; no. of ways - 729   3) X0XX00 ==&gt; no. of ways - 729   4) XX00X0 ==&gt; no. of ways - 729   5) X00XX0 ==&gt; no. of ways - 729   Probability = (729*5)/90000   =81/20000   Ans - 81/20000
<result>B</result>
In a 6 digit ID number, what is the probability of exactly four digits are the digit 0?