Final answer:
The number of cell phone users worldwide is about 19 times larger than the number of users in the United States.
Step-by-step explanation:
To find out how many times larger the number of cell phone users worldwide is than the number in the United States, we divide the worldwide number by the United States number. Given that there are approximately 300,000,000 cell phone users in the United States and 5.7 × 109 (which is 5,700,000,000) worldwide, we perform the following calculation:
Number of times larger = Worldwide users / United States users
Number of times larger = 5,700,000,000 / 300,000,000
Number of times larger = 19
Therefore, the number of cell phone users worldwide is about 19 times larger than the number in the United States.