Answer:
D. 10^10
Step-by-step explanation:
Multiplying numbers with exponents rule : 
explanation of rule : we simply keep the bases the same and add the exponents.
10^3 • 10^7
keep the base as 10 and add the exponents

Keep in mind that this only works when the bases are the same.
Answer:
7
Step-by-step explanation:
Answer:
The population of the town at the end of 2017 was 65,550.
Step-by-step explanation:
The population of the town was 60,000 in the beginning of 2016.
In 2016, the total population is increased by 15%.

Therefore the population is increased by 9000 and the population of the town at the end of 2016 was

In 2017, the total population is decreased by 5%.

Therefore the population is decreased by 3450 and the population of the town at the end of 2017 was

Therefore the population of the town at the end of 2017 was 65,550.
Answer:
if you meant x times y...
15 x 20 is 300.
if you meant x + y...
15 + 20 is 35.
if you meant anything else, please let me know
the way it was written confused me but I tried.