Percent of decrease
Just like the name suggests, the percent of decrease is the amount of decrease out of one hundred.
Once we know what the decrease is, just divide the decrease by the original amount and express the answer as a percent.
Thus, the formula to use is : Amount of decrease / Original amount
I will illustrate what I just said with examples.
Find the percent of decrease from 6 to 4.
Amount of decrease is 6 − 4 = 2
Original amount is 6
2 / 6 = 0.3333
multiply 0.3333 by one hundred to get the answer as a percent.
0.3333 × 100 = 33.33, so the answer is 33.33%.
Find the amount of decrease per hundred from 10 to 5.
Amount of decrease is 10 − 5 = 5
Original amount is 10
5 / 10 = 0.50
multiply 0.50 by one hundred to get the answer as a percent
0.50 × 100 = 50, so the answer is 50%.
Find the amount of increase per hundred from -4 to -8.
Amount of decrease is -4 − -8 = -4 + 8 = 4
Original amount is -4
4 / -4 = -1
multiply -1 by one hundred to get the answer as a percent
-1 × 100 = -100, so the answer is -100%.
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