Pay stubs & time sheets
NOTES: a quick overview of percents with the proportion method The proportion method is intuitive and suitable for all sorts of percent problems. What is a percent? Basically, it’s a part out of a whole, the whole being made up of 100 pieces. Given that, you can write this proportion:
𝑃 𝑊
=
%# 100
P = part
W = whole
% # = percent (number in front of the %)
If I eat 4 brownies out of a whole plate of 10, I’ve eaten 40% of the brownies.
To use this method, you’ll need to be able to identify the 3 pieces of a typical percent problem: the part, the whole, and the percent. Problems usually give you two of these and ask you to find the third.
How do I identify percent, part, and whole? The percent is the easiest to find. It’s the number in front of the percent sign (%) or the word “percent.” You’re taking some piece out of a whole, so the whole is frequently the number after the word “of.” Notice that the whole isn’t always bigger than the part! The part is the value that’s left over after you’ve found the other two. The “what” indicates the value you need to find. For this, just use a variable (such as n for number) or a question mark (?).
© D. Stark 2017
10/20/2017
OVERVIEW: percents with the proportion method
1
EXAMPLE #1: What is 35% of 150? % = 35
Whole = 150
Part = n (don’t know)
EXAMPLE #2: 20 is 25% of what number? Whole = n (don’t know)
% = 25
Part = 20
EXAMPLE #3: 120 is what percent of 80? [Notice the part is greater than the whole.] % = n (don’t know) Whole = 80 Part = 120
How do I solve the problem once I know percent, part, and whole? Put the values in the proper places in the proportion & solve for the missing value.
Type I: What is 35% of 150?
n 150
35 100
[finding the part]
ANSWER: 52.5
Type II: 20 is 25% of what number?
20 n
25 100
[finding the whole]
ANSWER: 80
Type III: 120 is what percent of 80?
120 n 80 100
.
[finding the percent]
n = 150
ANSWER: 150%
GED® is a registered trademark of the American Council on Education (ACE) and administered exclusively by GED Testing Service LLC under license. This material is not endorsed or approved by ACE or GED Testing Service.
© D. Stark 2017
10/20/2017
OVERVIEW: percents with the proportion method
2
𝑃 𝑊
=
%# 100
P = part
W = whole
% # = percent (number in front of the %)
If I eat 4 brownies out of a whole plate of 10, I’ve eaten 40% of the brownies.
To use this method, you’ll need to be able to identify the 3 pieces of a typical percent problem: the part, the whole, and the percent. Problems usually give you two of these and ask you to find the third.
How do I identify percent, part, and whole? The percent is the easiest to find. It’s the number in front of the percent sign (%) or the word “percent.” You’re taking some piece out of a whole, so the whole is frequently the number after the word “of.” Notice that the whole isn’t always bigger than the part! The part is the value that’s left over after you’ve found the other two. The “what” indicates the value you need to find. For this, just use a variable (such as n for number) or a question mark (?).
© D. Stark 2017
10/20/2017
OVERVIEW: percents with the proportion method
1
EXAMPLE #1: What is 35% of 150? % = 35
Whole = 150
Part = n (don’t know)
EXAMPLE #2: 20 is 25% of what number? Whole = n (don’t know)
% = 25
Part = 20
EXAMPLE #3: 120 is what percent of 80? [Notice the part is greater than the whole.] % = n (don’t know) Whole = 80 Part = 120
How do I solve the problem once I know percent, part, and whole? Put the values in the proper places in the proportion & solve for the missing value.
Type I: What is 35% of 150?
n 150
35 100
[finding the part]
ANSWER: 52.5
Type II: 20 is 25% of what number?
20 n
25 100
[finding the whole]
ANSWER: 80
Type III: 120 is what percent of 80?
120 n 80 100
.
[finding the percent]
n = 150
ANSWER: 150%
GED® is a registered trademark of the American Council on Education (ACE) and administered exclusively by GED Testing Service LLC under license. This material is not endorsed or approved by ACE or GED Testing Service.
© D. Stark 2017
10/20/2017
OVERVIEW: percents with the proportion method
2
