physics
posted by john .
The cabin noise level of the new Airbus 380 is 5 decibels lower than that of a 747 Jumbo Jet. By what factor does the noise intensity decrease?

db = 10log(p2/p1) = 5.
The negative sign means p2 is less than p1 and the ratio is less yhan 1.
10log(p2/p1) = 5,
Divide both sides by 10:
log(p2/p1) = 0.5,
p2/p1 = 10^0.5 = 0.316. 
db = 10log(p2/p1) = 5.
10log(p2/p1) = 5,
Divide both sides by 10:
log(p2/p1) = 0.5,
p2/p1 = 10^0.5 = 3.16.