# Math Help - Alexander Graham Bell Problem

1. ## Alexander Graham Bell Problem

The loudness of sound is measured in decibels in honor of Alexander Graham Bell (1847-1922), inventor of the telephone. If the variation in pressure is P pounds per square inch, then the loudness L in decibels is $L = 20 \log_{10}(121.3 P)$

Find the variation in pressure caused by a rock band at 115 decibels.
i have no clue on how to start this one.

2. Originally Posted by viet
i have no clue on how to start this one.
you start by substituting 115 for L of course, then solve for P. do you have problems solving the logarithmic equation?

3. i seem to make it harder than it really is. thanks Jhevon