goods81 wrote:
Look at it this way...
let's say N=2
what is 100% of 2? 4 (2*2)
what is 200% of 2? 6 (2*3)
what is 800* of 2? 18 (2*9)
There's a difference between the question "What is 800% of 2", and "What is the result if 2 is increased by 800%?"
If we need to find 800% of 2, we multiply 2 by 800% = 800/100 = 8. That is, 800% of 2 is equal to 8*2 = 16.
On the other hand, if we need to
increase 2 by 800%, we need to add 800% of 2 to 2. It may be easier to remember:
original value + increase = final value
So to increase 2 by 800%, we have:
2 + (800/100)*2 = 2 + 16 = 18
Of course, if we increase something by 800%, we're really multiplying it by 9, not by 8.
We can see why increasing something by 800% is the same as multiplying something by 9 by using factoring. Let's do that for any percent increase at all. Say we increase 2 by x%. Then the result would be equal to:
2 + (x/100)*2 = 2(1 + x/100)
So when we increase something by x%, we're really multiplying it by (1+x/100), and not just by x/100.
