Example 6.24 from Prealgebra, 6.2 Solve General Applications of Percent

Solve General Applications of Percent: example 6.24

The average price of a gallon of gas in one city in June $2014$ was $$3.71 .$ The average price in that city in July was $$3.64 .$ Find the percent decrease.

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

The population of one city was about $672,000$ in $2010 .$ The population of the city is projected to be about $630,000$ in $2020 .$ Find the percent decrease. (Round to the nearest tenth of a percent.)

How did it go?

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

What are you asked to find?	the percent decrease
Choose a variable to represent it.	Let $p =$ percent.
Find the amount of decrease.
Find the percent of decrease.	The decrease is what percent of the original amount?
Translate to an equation.
Divide both sides by 3.71.
Round to the nearest thousandth.
Convert to percent form.
Write a complete sentence.	The price of gas decreased 1.9%.

What are you asked to find?	the percent decrease
Choose a variable to represent it.	Let $p =$ percent.
Find the amount of decrease.
Find the percent of decrease.	The decrease is what percent of the original amount?
Translate to an equation.
Divide both sides by 3.71.
Round to the nearest thousandth.
Convert to percent form.
Write a complete sentence.	The price of gas decreased 1.9%.

Solve General Applications of Percent: example 6.24

Solution

Your turn

Solve General Applications of Percent: example 6.24

Solution

Your turn