Sound intensity question

[med55]

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Hi, I cannot understand the answer to this question:

If the intensity of a sound wave is reduced by 90%, by how much does its sound level decrease?
answer: 10dB

Help would be appreciated!

 

[JFK90787]

Use the equation Sound Level (also called Intensity level or loudness)=10logI/Io. Decreasing I by 90% is like multiplying it by 10^-1. Multiplying the right by 10^-1 means you need to subtract 10dB from the left.

 

[med55]

So essentially like dividing the I by 10. Got it, thanks!