What is the Correct Way to Calculate Relative Improvement and Percentage?

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The calculation of relative improvement from 10 to 8 was incorrectly stated as 25%. The correct formula should yield a negative result, indicating a decrease, specifically -25%. To clarify, reducing a number by 25% means subtracting a quarter of the original value, resulting in 7.5 when applied to 10. Therefore, the relative improvement should reflect the decrease accurately. Understanding these calculations is essential for proper interpretation of percentage changes.
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Homework Statement


Hi guys

Say I go from 10 to 8. Is the relative improvement given by

(1-10/8) = 0.25,

i.e. 25%?


Niles.
 
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First of all, you forgot the sign. The result of your formula should have been -25%, which makes sense because the 2nd value is less than the first.

Secondly, that is not correct. Think about it this way: to decrease some number by 25% means to take 1/4 of the original number away.
In other words X - (0.25)X which is equal to 0.75X.

In your case, decreasing 10 by 25% gives you (0.75) * 10 = 7.5
 

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