What is the probability of creating a three digit number with exactly two consecutive primes as digits?  Choose the correct answer
A) 3/100  B) 9/250  C) 9/125  D) 21/250  E) 51/500
For numbers between 100- 199   For 1 st digit we just have 1 option   For second digit we have 3 options (2,3,5) and for all these 3 options we have one option ( i.e for 2 we have 3, for 3 we have 5 and for 5 we have 7)   Hence for numbers between 100-199 we have in total 3 options   Now for numbers between 200-299   For 1st digit again we have only one option but now for 2nd we have either 1 option i.e 3 or we have 8 options i.e when 3rd digit is 3 ( so when 3rd digit is 3 we have 8 options for 2nd digit.)   Hence in total 1* 2* 8 ( 2 because we 2 places for placing 3 ) = 16   Now, similarly for numbers starting from 300-399 we will have same 32 options and same goes for other numbers   So now using PO51/500 we can clearly see the total numbers will be more than 21 for sure,   Hence 51/500
<result>E</result>
What is the probability of creating a three digit number with exactly two consecutive primes as digits?