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This module is from Elementary Algebra by Denny Burzynski and Wade Ellis, Jr. This chapter contains many examples of arithmetic techniques that are used directly or indirectly in algebra. Since the chapter is intended as a review, the problem-solving techniques are presented without being developed. Therefore, no work space is provided, nor does the chapter contain all of the pedagogical features of the text. As a review, this chapter can be assigned at the discretion of the instructor and can also be a valuable reference tool for the student.

Overview

  • The Meaning of Percent
  • Converting A Fraction To A Percent
  • Converting A Decimal To A Percent
  • Converting A Percent To A Decimal

The meaning of percent

The word percent comes from the Latin word “per centum,” “per” meaning “for each,” and “centum” meaning “hundred.”

Percent (%)

Percent means “for each hundred” or “for every hundred.” The symbol % is used to represent the word percent.

Thus, 1 % = 1 100 or 1 % = 0.01.

Converting a fraction to a percent

We can see how a fraction can be converted to a percent by analyzing the method that 3 5 is converted to a percent. In order to convert 3 5 to a percent, we need to introduce 1 100 (since percent means for each hundred).

3 5 = 3 5 · 100 100 Multiply the fraction by 1 . = 3 5 · 100 · 1 100 Since   100 100 = 100 · 1 100 . = 300 5 · 1 100 Divide  300  by 5 . = 60 · 1 100 Multiply the fractions . = 60 % Replace  1 100 with the  %  symbol .

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Fraction to percent

To convert a fraction to a percent, multiply the fraction by 1 in the form 100 · 1 100 , then replace 1 100 with the % symbol.

Sample set a

Convert each fraction to a percent.

1 4 = 1 4 · 100 · 1 100 = 100 4 · 1 100 = 25 · 1 100 = 25 %

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8 5 = 8 5 · 100 · 1 100 = 800 5 · 1 100 = 160 %

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4 9 = 4 9 · 100 · 1 100 = 400 9 · 1 100 = ( 44.4... ) · 1 100 = ( 44. 4 ¯ ) · 1 100 = 44. 4 ¯ %

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Converting a decimal to a percent

We can see how a decimal is converted to a percent by analyzing the method that 0.75 is converted to a percent. We need to introduce 1 100 .

0.75 = 0.75 · 100 · 1 100 Multiply the decimal by 1 . = 75 · 1 100 = 75 % Replace  1 100  with the % symbol .

Decimal to percent

To convert a fraction to a percent, multiply the decimal by 1 in the form 100 · 1 100 , then replace 1 100 with the % symbol. This amounts to moving the decimal point 2 places to the right.

Sample set b

Convert each decimal to a percent.

0.62 = 0.62 · 100 · 1 100 = 62 · 1 100 = 62 %

Notice that the decimal point in the original number has been moved to the right 2 places.

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8.4 = 8.4 · 100 · 1 100 = 840 · 1 100 = 840 %

Notice that the decimal point in the original number has been moved to the right 2 places.

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0.47623 = 0.47623 · 100 · 1 100 = 0.47623 · 1 100 = 47.623 %

Notice that the decimal point in the original number has been moved to the right 2 places.

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Converting a percent to a decimal

We can see how a percent is converted to a decimal by analyzing the method that 12% is converted to a decimal. We need to introduce 1 100 .

12 % = 12 · 1 100 Replace % with 1 100 . = 12 100 Multiply the fractions . = 0.12 Divide 12 by 1 00.

Percent to decimal

To convert a percent to a decimal, replace the % symbol with 1 100 , then divide the number by 100. This amounts to moving the decimal point 2 places to the left.

Sample set c

Convert each percent to a decimal.

48 % = 48 · 1 100 = 48 100 = 0.48

Notice that the decimal point in the original number has been moved to the left 2 places.

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659 % = 659 · 1 100 = 659 100 = 6.59

Notice that the decimal point in the original number has been moved to the left 2 places.

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0.4113 % = 0.4113 · 1 100 = 0.4113 100 = 0.004113

Notice that the decimal point in the original number has been moved to the left 2 places.

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Exercises

For the following problems, convert each fraction to a percent.

For the following problems, convert each decimal to a percent.

For the following problems, convert each percent to a decimal.

Questions & Answers

how did you get 1640
Noor Reply
If auger is pair are the roots of equation x2+5x-3=0
Peter Reply
Wayne and Dennis like to ride the bike path from Riverside Park to the beach. Dennis’s speed is seven miles per hour faster than Wayne’s speed, so it takes Wayne 2 hours to ride to the beach while it takes Dennis 1.5 hours for the ride. Find the speed of both bikers.
MATTHEW Reply
420
Sharon
from theory: distance [miles] = speed [mph] × time [hours] info #1 speed_Dennis × 1.5 = speed_Wayne × 2 => speed_Wayne = 0.75 × speed_Dennis (i) info #2 speed_Dennis = speed_Wayne + 7 [mph] (ii) use (i) in (ii) => [...] speed_Dennis = 28 mph speed_Wayne = 21 mph
George
Let W be Wayne's speed in miles per hour and D be Dennis's speed in miles per hour. We know that W + 7 = D and W * 2 = D * 1.5. Substituting the first equation into the second: W * 2 = (W + 7) * 1.5 W * 2 = W * 1.5 + 7 * 1.5 0.5 * W = 7 * 1.5 W = 7 * 3 or 21 W is 21 D = W + 7 D = 21 + 7 D = 28
Salma
Devon is 32 32​​ years older than his son, Milan. The sum of both their ages is 54 54​. Using the variables d d​ and m m​ to represent the ages of Devon and Milan, respectively, write a system of equations to describe this situation. Enter the equations below, separated by a comma.
Aaron Reply
find product (-6m+6) ( 3m²+4m-3)
SIMRAN Reply
-42m²+60m-18
Salma
what is the solution
bill
how did you arrive at this answer?
bill
-24m+3+3mÁ^2
Susan
i really want to learn
Amira
I only got 42 the rest i don't know how to solve it. Please i need help from anyone to help me improve my solving mathematics please
Amira
Hw did u arrive to this answer.
Aphelele
hi
Bajemah
-6m(3mA²+4m-3)+6(3mA²+4m-3) =-18m²A²-24m²+18m+18mA²+24m-18 Rearrange like items -18m²A²-24m²+42m+18A²-18
Salma
complete the table of valuesfor each given equatio then graph. 1.x+2y=3
Jovelyn Reply
x=3-2y
Salma
y=x+3/2
Salma
Hi
Enock
given that (7x-5):(2+4x)=8:7find the value of x
Nandala
3x-12y=18
Kelvin
please why isn't that the 0is in ten thousand place
Grace Reply
please why is it that the 0is in the place of ten thousand
Grace
Send the example to me here and let me see
Stephen
A meditation garden is in the shape of a right triangle, with one leg 7 feet. The length of the hypotenuse is one more than the length of one of the other legs. Find the lengths of the hypotenuse and the other leg
Marry Reply
how far
Abubakar
cool u
Enock
state in which quadrant or on which axis each of the following angles given measure. in standard position would lie 89°
Abegail Reply
hello
BenJay
hi
Method
I am eliacin, I need your help in maths
Rood
how can I help
Sir
hmm can we speak here?
Amoon
however, may I ask you some questions about Algarba?
Amoon
hi
Enock
what the last part of the problem mean?
Roger
The Jones family took a 15 mile canoe ride down the Indian River in three hours. After lunch, the return trip back up the river took five hours. Find the rate, in mph, of the canoe in still water and the rate of the current.
cameron Reply
Shakir works at a computer store. His weekly pay will be either a fixed amount, $925, or $500 plus 12% of his total sales. How much should his total sales be for his variable pay option to exceed the fixed amount of $925.
mahnoor Reply
I'm guessing, but it's somewhere around $4335.00 I think
Lewis
12% of sales will need to exceed 925 - 500, or 425 to exceed fixed amount option. What amount of sales does that equal? 425 ÷ (12÷100) = 3541.67. So the answer is sales greater than 3541.67. Check: Sales = 3542 Commission 12%=425.04 Pay = 500 + 425.04 = 925.04. 925.04 > 925.00
Munster
difference between rational and irrational numbers
Arundhati Reply
When traveling to Great Britain, Bethany exchanged $602 US dollars into £515 British pounds. How many pounds did she receive for each US dollar?
Jakoiya Reply
how to reduced echelon form
Solomon Reply
Jazmine trained for 3 hours on Saturday. She ran 8 miles and then biked 24 miles. Her biking speed is 4 mph faster than her running speed. What is her running speed?
Zack Reply
d=r×t the equation would be 8/r+24/r+4=3 worked out
Sheirtina
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Source:  OpenStax, Elementary algebra. OpenStax CNX. May 08, 2009 Download for free at http://cnx.org/content/col10614/1.3
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