Final answer:
City X with a population of 3 x 10^5 has fewer inhabitants than City Y with a population of 6 x 10^6. Thus, the population of City X is less than that of City Y.
Step-by-step explanation:
City X has a population of 3 x 10^5 and City Y has a population of 6 x 10^6. To compare these numbers, we should look at the exponent of 10, which represents how many times we multiply the number by 10. The exponent 5 in City X's population means we multiply 3 by 10 five times (3x10x10x10x10x10), giving us 300,000. On the other hand, the exponent 6 in City Y's population means we multiply 6 by 10 six times (6x10x10x10x10x10x10), resulting in 6,000,000.
Because 6,000,000 is greater than 300,000, the correct statement describing the relationship between the populations of City X and City Y is:
B) The population of City X is less than the population of City Y.