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in the problem what percent of 20 is 30 how do you get the 1.5

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4 Answers

What percent of 20 is 30? 
If you divided 20 into 100 equal parts, how many of them would you need to make 30?
20/100=2/10=1/5  How many 1/5's in 30.  There are 5 for each one and 30 ones. You need 150.
30 is 150 percent of 20.
Whenever you see the word "IS," in a math problem, think EQUAL.
 
what percent of 20 is 30
what percent of 20 = 30
 
 
Since 30 is larger than 20, your percentage will be larger than 100%. (100% of 20 = 20)
 
 
You can turn this into a proportion (fraction), with 20 as your denominator (total # of something), and 30 as your numerator (# of parts of something). Right away, we can reduce by crossing out both zeros, which comes out to 3/2. You can either divide it out by hand, or throw it into your calculator, which will result in 1.5.
 
 
 
You can also turn this into an algebraic equation (another skill set on your GED test that they'll be asking you about!).
 
what percent of 20 is 30
 
Make "what percent," your X, and substitute and equal sign for "is."
 
X of 20 = 30
 
"Of" = multiply
 
x20 = 30
 
In math, we always list the coefficient (number) before the x.
 
20x = 30
 
To simplify this, we divide 20 into 30. We end up with:
 
x = 30/20
 
Reduce it down (cross out both zeros, since we have one zero on top and one on the bottom- note that this ONLY works if there is an even number of zeros on top and bottom).
 
x = 3/2, or 1.5
 
 
 
 
 
The trick here is to turn 1.5 back into a percentage.
 
When we convert percentages into decimals, all we do is move the decimal over TWO places.
 
For example:
 
100% = 100.0%
 
Therefore,
 
100.0% = 1.000
 
(See what I did there? Just moved the decimal two places to the left. Nothing fancy at all. Really, it's that simple.)
 
 
 
To make 1.5 into a percentage, we need to move the decimal in the opposite direction (right).
 
1.5 = 150.0%
 
I'm leaving the decimal there to help illustrate the example, but if you have a decimal of (number).000, you can simply drop the decimal completely. ;-)
 
Hope that helps!
 
this formula may help
 
percentage=rate x base
percentage is the IS number, base is the OF number, and rate is the %
you have the percentage (30, the IS number)
you have the base (20, the OF number)
the rate (the percent) is missing (it says what percent)
substitute into the formula
30=rate*20
let r = rate
30= r*20
30/20=r
1.5=r, the rate
change 1.5 to a percent and get 150%
 
 
Hi Kelly,
 
Try thinking about it this way, if you were taking 20% of 80 you would get 16 (80 x 0.2=16).  
 
Now I believe what this question is asking for  20 * percentage=30, so you can solve for the decimal of the percentage 30/20, which is 1.5.  So the percentage would be 1.5 x 100 = 150%.
 
I hope this helps.

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