Answer: 0.3 .
Step-by-step explanation:
The digits in number system = 10 ( 0 to 9)
The total different nine-digit Social security numbers = [By Fundamental counting principle]
= 1 billion
Total people in united state = 300 million = 300, 000 ,000
Since each person In US have equal chance to get chosen.
Therefore , if a number is selected randomly , then the probability that it belongs to one of the 300 million people in the United States :-
Hence, the required probability is 0.3 .