Sound question

[dahmsom]

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how is the answer 316 farther away?? How would u approach this question? I know that intensity Inversely proportional to the radius squared . Why would u take the square root of 10000? I'm not understanding the formula

 

[basophilic]

Use the decibel equation: the general equation is B (beta) = 10 log(I/I0). If you find the difference between the two decibel levels mentioned in question, you can get a ratio of the intensities emitted by the two sounds: B2 - B1 = 10 log(I2/I1)
So: 100-50 = 50 = 10 log(I2/I1) --> hence, I2/I1 = 10^5
Since you know that intensity is inversely proportional to the radius squared: I2/I1 = (r1/r2)^2 = 10^5
The sqrt of 100,000 will give the answer