Question 1200386
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Answer: <font color=red size=4>15% decrease</font>



Work Shown:
a = old value = 200
b = new value = 170
c = change in values
c = b-a 
c = 170-200
c = -30
The negative c value tells us that we have a percent decrease.


Then divide over the starting value a = 200
c/a = -30/200 = -0.15
Move the decimal point two spots to the right to go from 0.15 to 15%
Or multiply 0.15 with 100% to get 0.15*100% = 15%


We have a <font color=red>decrease of 15%</font>


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Another approach:
a = old value = 200
b = new value = 170
b/a = ratio of new over old
b/a = 170/200 = 0.85


Subtract off 1 to get 0.85-1 = -0.15 which then converts to -15%
The negative percentage indicates percent decrease.


Here's a handy calculator to check your work.
<a href = "https://www.calculatorsoup.com/calculators/algebra/percent-change-calculator.php">https://www.calculatorsoup.com/calculators/algebra/percent-change-calculator.php</a>
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