急 ! Logarithmic Function 9q12

9) Suppose that M is the absolute magnitude of the earthquake in region A, then 15 M will be the absolute magnitude of the earthquake in region B, with Ritcher Scale:

log 15M = log 15 + log M = 6.6

30b) Suppose that I is the intensity of the sound from the building street, then 70I will be the intensity of that from the building site.

Then the intensity level from building site will be more that that from the street by:

10 log 70I - 10 log I = 10 log 70 = 8 dB