In a 5 digit ID number, what is the probability of exactly three digits are the digit 0?
Answers
A) 12/2507
B) 9/2500
C) 11/9800
D) 13/2500
E) 14/2751
Total number of 5 digit numbers = 99999-10000+1=90,000   No. of ways of arranging 3 digits as 0 = 4C3=4.   Arrangements are as follows. Here X can be any digit other than 0   1) X000X ==&gt; no. of ways - 81   2) XX000 ==&gt; no. of ways - 81   3) X0X00 ==&gt; no. of ways - 81   4) X00X0 ==&gt; no. of ways - 81   Probability = (81*4)/90000   =9/2500   Ans - 9/2500
<result>B</result>
In a 5 digit ID number, what is the probability of exactly three digits are the digit 0?