# Decibel increase

1. Nov 29, 2009

### ryty

1. The problem statement, all variables and given/known data
In a pig-calling contest, a caller produces a sound with an intensity level of 90 dB. How many such callers would be required to reach the pain level of 120 dB?

2. Relevant equations
i dont know

3. The attempt at a solution
The way I understood it from my book, for every multiple of ten increase in decibels, you have to multiply by that number, so i multiplied 1 by 3, to get 3, but that isnt right.

2. Nov 29, 2009

### cepheid

Staff Emeritus
No, for every factor of ten increase in the sound intensity, you add 10 dB.

3. Nov 29, 2009

### ryty

So how do i find how many callers it takes to go from 90-120dB

4. Nov 29, 2009

### cepheid

Staff Emeritus
That's why listing the relevant equations is important, rather than just saying "I don't know." What is the *definition* of sound intensity in decibels? That equation is certainly given in your book, and is obviously a piece of information that you need to know before you can begin to answer questions about sound intensities in dB. Post that equation, and tell me if you are able to see, from it, how to proceed. If not, I can provide further hints.