(Always reduce the fraction)Math 094 Mod. IV Notes
Chapter 2
Percents
Percent is another method of expressing fractions or parts of any object. Percents are expressed in terms of hundredths, so 100% means 100 hundredths or 1.
i.e. Percent (per hundred) -A number divided by 100
(written with a % symbol behind it)
What does 65% mean (Always reduce the fraction)
From this chapter you will want to study the methods of converting fractions to decimals and percents . You will also need to know how to convert from percents to fractions and decimals.
Fractions Þ Decimals
Example: 
, we do division to get a decimal 
= 1.6 ( see Mod. III)
If it is a mixed number, keep the integer and convert the improper fraction to decimal, then put them together.
Example: 
, do the division 
so the answer is 3.4
Decimals Þ Fractions
Example: 2.125 we have three decimal places so we use 1000 (with three 0) as denominator Þ 2.125 = 
(Always reduce fraction to the lowest term.)
Percent Þ Fraction
Put 
and drop % sign, reduce if necessary
Example: 
Example: 
Example: 
Fraction Þ Percent
Set fraction = 
and solve for x as decimal and add % sign
Example: 
, cross-multiplying to get 8x = 300 Þ 
Don't forget add % behind the number, the answer is 
OR: Multiply the fraction by 
, it is equivalent to multiply by 1, then switch the 100 from the denominator to the side as a % symbol and multiply the fraction by 100.
Example: 
Percent Þ Decimal
If the percent already has a decimal point then move it two places to the left and drop % sign
Example: 20.3% = 0.203
Example: 0.78% = 0.0078
If it does not have a decimal point, then put one at the end of the last digit and then move it two places to the left and drop % sign
Example: 5% = 5.% = 0.05
Decimal or Whole # Þ Percent
If it already has a decimal point then move it two places to the right and add % sign.
Example: 0.056 = 5.6%
If it does not have a decimal point then put one at the end of the last digit and then
move it two places to the right and put % sign
Example: 32 = 32. = 3200%
OR: Multiply the decimal by , it is equivalent to multiply by 1, then switch the 100 from the denominator to the side as a % symbol and multiply the decimal by 100.
Example: 
Example: 
Word problems concerning percents come in the following varieties:
1. What is x percent of y ?
2. x is what percent of y ?
Each can be solved using ratios but the set up of the ratios will be different depending on the type of question presented . If we want to know what 15% of 130 is we set up the following ratio:
In the second type of problem we see the words 'what percent' which translate to
?/100 . For example if we the question reads '7 is what percent of 49 ?' we set up the following ratio:
Some of the more interesting percent problems involve sale prices . For example:
If a dress is purchased for 186.00 on sale at a 20% discount what was the original price of the dress ? One way to approach this problem is to look at the $186.00 purchase price as it relates to the original price . 186.00 is 20% less than the original price therefore it can also be thought of as 80% of the original price (think of the original price as the 100% price).
x in this ratio represents the original price .