So the change in population is 9,000. The percentage of population loss is just the change in population divided by the original population.

Turn 0.134 into a percent so that we get 13.4%.  So the percent of population loss is 13.4%.

To find the percent decrease, we need to calculate the difference between the original (larger) amount of land and the final (smaller) amount. Here, this difference is  acres. This value refers to the amount of decrease. We now need to convert it into a percent.

To do so, we use a proportion: .

Cross-multiplication shows us that  is equal to

 , so percent.

Write the formula to find percent decrease:

Subsitute the values into the formula.

The approximate percent decrease is .

To find the percentage that the original price decreased, use the following relation:

Now, to find the percentage, simply multiply the decimal by 100.

If the amount of houses decreased by 85%, that means the amount that remain is 100% - 85%, or 15%. We want to find 15% of 70%. Since we're leaving our answer as a percentage, we can just leave 70% as 70, and convert 15% to 0.15 and multiply:

.

This means our answer is 10.5%.

To figure out the percent change, we want to figure out the amount that the population changed. We can do this by subtracting:

Now we want to figure out what percent that change was of the original. In other words, 111,549 is what percent of 501,662. We can write that as a solvable equation knowing that "of" means multiply:

divide both sides by 501,662

multiply by 100 to convert this decimal into a percentage

To find the percent change of two numbers, you use the formula: 

.

This formula in the context of this question: 

.

Thus, now know that if we subtract about forty six percent of the original number from the original number, we would get the second number. We have about a forty six percent decrease. 

To find the percent of decrease from one number to the next we use the formula: 

In this case, the difference is 

.

So our formula would be 

.

From  to  is about a  decrease. 

To calculate the percent decrease in a price, quantity etc. you need to establish a ratio between the new and lower price and the old, higher price. Then convert to a percentage by multiplying by 100.

Establish a ratio between the new and the old:

Convert to a percentage:

 percent

So the parental discount amounts to 72% of the old price. In other words with their help, you will only pay 72% of the original price. Because you are now paying only 72% of that price, that was a decrease of 28%  (100-72=28%).

Alternatively find the difference between the two prices, divide by the original price, and multiply by 100. Try this method to see that you get the SAME answer.