The population of a city is 45,000 and decreases 2% each year. if the trend continues, what will the population be after 15 years

The answer is 31,500.
Let's clarify some things :
1% of 45,000 is 450
Maybe you're wondering why , it's actually very simple .
Just move the decimal to the left once if you want to find 10% , move the decimal twice if you want to find 1%.
We now that 1% equals 450. Then 2% equals to
Well just add another 1% .
450 + 450 or 450 times 2
Which equals 900.
Now we want to find what's the population after 15 years.
900 times 15= 13,500
But that's not the answer
That's what is decreasing.
45,000 - 13,500= 31,500
That's why the answer is 31,500.

The sample observations are not a random​sample, so a test about a population proportion using the normal approximating method cannot be used.

Step-by-step explanation:

The necessary conditions are

The sample must be random and independently selected from the normally distributed population.

n*p and n*q both must be greater than 5

There must be two outcomes "success" and "failure"

The number of trials must be fixed.

From the given information 2), 3)and 4) conditions are satisfied, but not 1) because we are not given that people are selected randomly.

The sample observations are not a random​sample, so a test about a population proportion using the normal approximating method cannot be used.