I forgot the last digit of a 7-digit telephone number. If 1 randomly dial the final 3 digits after correctly dialling the first four, then what is the chance of dialling the correct number?
Pick one:
A) 1/1001.	B) 1/1000	C) 1/999	D) 1/990	E) 1/968
Explanation :   Given, the last three digits are randomly dialled, then each of the digit can be selected out of 10 digits in 10 ways.   Hence, the required probability is:-   =&gt;(1/10)3.   =&gt;1/1000.   Answer : 1/1000
<result>B</result>
I forgot the last digit of a 7-digit telephone number. If 1 randomly dial the final 3 digits after correctly dialling the first four, then what is the chance of dialling the correct number?