I have been surprised lately by some common errors made when people are calculating/reporting percentages. At first I thought it was just one person who made a simple mistake, but in a matter of a week, I saw 4 people make similar errors. Maybe those are the only 4 people to make this mistake, but I had to post this in the event that I might spare you from making this type of error too. Here is an example:
By what percentage is $1400 higher than $600?
Typical incorrect response: (1400-600)/1400=57%
One way to show that this is incorrect is to add 57% of 600 to 600: (600 *0.57 )+ 600=943
The correct response is: (1400-600)/600=133%
Now, if the question was phrased as "By what percentage is $600 lower than $1400?" the answer of 57% would be correct. It is all about choosing the correct base number to answer the question being asked.
3 comments:
Either that or not understanding word problems.
Isn't tackling "word" problems your specialty?
I leave word problems to the math teachers.
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