Amplitude problems
If sound A has 10 times the SPL of sound B, how much louder is A than B in dB?
dB = 20 log10 10 = 20 dB louder
If sound A is 100 db and sound B is 80 db, how much louder is A than B?
If an 80 db sound is combined with a 40 db sound, how loud is the sound (approximately)?