Math Help Percent Increase
January 17th, 2007
Question: I need a help with a math question. Percent increase?
What is the percent increase from 0 to 1?
Think:
It -IS- possible for something to become 1 from 0.
it -IS- possible to do “the % increase from 50 to 75 is 50%”
So what’s the percent increase from 0 to 1? it’s no infinity. infinity * 0 = 0… or does it?
Thanks in advance =)
Answer: This is one of those questions that teachers dream about not getting. In other words, it’s a great question, but one that is really hard to answer.
Start with your example.
To get the percent increase you do ((75-50)/50)*100. Now look what happens when you try your problem.
((0-1)/0) * 100 =
That’s why we say you cannot divide by zero. You get results that are really strange.
Here’s another example. It is usually shown in a grade 9 or 11 algebra class.
a = b Multiply both sides by a
a*a = b*a Now subtract b*b from both sides
a*a – b*b = b*a – b*b Now factor. You may not have been told how to do this, If not, write me.
(a-b)*(a+b) = b*(a-b) Now divide by the common factor (a-b)
a+b = b Now here’s the kicker. Since a = b you can put in b for the a on the left hand side.
b + b = b. OH OH.
2b = b Now divide by b. No matter what you think the answer on the right is, it’s not 2. In fact you get
2 = 1. Why did that happen? Hint look at the step with a-b divided on both sides.
Zero is the most unruly number in the whole number system. It deserves our utmost respect.
Percentage Increase and Decrease
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