You hear sounds at the following decibel levels: 5 db, 10 db, 20 db, and 40 db. which sound is 10 times higher than the lowest pressure humans can hear?
40 db
10 db
20 db
5 db

the lowest pressure the human can hear is 20 micro Pa or 20x10^-6 Pa.

to convert it dB = 20 log ( p / p0 )

where p is the pressure you want to hear

p0 is the lowest pressure the human can hear

since you want 10 times higher the lowest possible

p/p0 = 10

dB = 20 log ( 10 )

dB = 20 dB

Explanation: