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Identify the percent of change as an increase or a decrease then find the percent of change. Round to the nearest tenth of a percent if needed

 

question #1  120 pounds to 180

 

question #2 10ft to 8ft

Nerd123  Jan 30, 2018
 #1
avatar+7339 
+3

1.

180  is bigger than  120  so this is an increase.

 

120  increased by what percent of  120  is  180   ?

 

Let  x  be the percent of increase.

 

120  +  120x   =   180

 

120x   =   60

 

x   =   60/120   =   0.5   =   50/100   =   50%

 

120  increased by  50%  of  120  is  180 .

 

2.

8  is smaller than  10  so this is a decrease.

 

10  decreased by what percent of  10  is  8    ?

 

10 - 10x  =  8

 

-10x  =  -2

 

x   =   -2 / -10   =   20 / 100   =   20%

 

10  decreased by  20%  of  10  is  8 .

hectictar  Jan 30, 2018
 #2
avatar+92596 
+2

Thanks for that good answer, hectictar.......here's another way to do this......

 

We can actually  use the same "formula" to figure both of these

 

% increase / decrease   =    (  l New Value - Old Value l  / Old Value  x 100 ) %

 

So...for the first one we have

 

(   l  180 - 120 l  /  120  x 100) %  =

 

(  l   60  l   /  120   x 100 ) %  =

 

(  60  / 120  x 100 ) %   =

 

( 1 / 2  x 100 ) %  =

 

50%  increase

 

 

For the second one, we have

 

(  l  8  - 10  l  /  10   x 100 ) %    =

 

(  l -2 l  / 10  x 100 ) %  =

 

(  2  / 10  x 100 ) %  =

 

( 1 / 5  x 100 ) %  =

 

20%  decrease

 

 

cool cool cool

CPhill  Jan 30, 2018

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