So I'm a big fan of percentages and decimals. I'll take them over fractions any day.
However I just ran across an anomaly that I'm sure is quite commonly discussed but I don't know how to search for it.
When you increase a number by a percent, you can not decrease the result by the same percent and receive the original number.
Therefore:
If a man is 100 years old and his friend is 125 years old, you can say his friend is 25% older than he is.
HOWEVER
If you word it differently you can not say that he is 25% younger than his friend. You would have to say that he is 20% younger.
Now I get what's happening here. The greater the number, the greater the addition or subtraction when increasing or decreasing by percent. 25% of 125 is 31.25 while 25% of 100 is 25. We have to move down 20% for every 25% we go up. If we decrease by 25% we'll get diminishing returns.
Is there a name for this? Is there an easy way of explaining it? Is it a well known occurrence in finance, architecture or other professions heavily into numbers?
However I just ran across an anomaly that I'm sure is quite commonly discussed but I don't know how to search for it.
When you increase a number by a percent, you can not decrease the result by the same percent and receive the original number.
Therefore:
If a man is 100 years old and his friend is 125 years old, you can say his friend is 25% older than he is.
HOWEVER
If you word it differently you can not say that he is 25% younger than his friend. You would have to say that he is 20% younger.
Now I get what's happening here. The greater the number, the greater the addition or subtraction when increasing or decreasing by percent. 25% of 125 is 31.25 while 25% of 100 is 25. We have to move down 20% for every 25% we go up. If we decrease by 25% we'll get diminishing returns.
Is there a name for this? Is there an easy way of explaining it? Is it a well known occurrence in finance, architecture or other professions heavily into numbers?
