Answer:
5.0
Explanation:
If we call the intensity of the larger quake I2, and that of the smaller quake I1, then we want to find I2/I1.
The log of that ratio is given by ...
log(I2/I1) = log(I2) -log(I1)
= R2 -R1
= 8.2 -7.5
log(I2/I1) = 0.7
Taking antilogs, we have ...
I2/I1 = 10^0.7
I2/I1 = 5.0
The stronger quake is 5.0 times as intense as the lesser one.