Steven W. answered 07/22/19
Physics Ph.D., college instructor (calc- and algebra-based)
The definition of sound intensity (β) level in decibels is: β = 10(log(I/I_o)), where I is the intensity of the sound in question.
You thus have to solve 136 = 10(log(I/I_o)) for I, using the given value of I_o you stated. If you need help doing that, please let me know