Exponent/Logarithm Problem Solving Help

I have a couple of questions that i need help withh :

1. Suppose a radio is playing loudly at a sound level of 80 decibels. What decibel level would make the radio sound one-fourth as loud?

how are you suppose to start this question? you don't use the decibel scale do you?

2. Show that a sound with d decibels has intensity E0(10)^(d/10), where E0 is the intensity of a sound with 0 decibels.

I have no idea what that question is asking for. D:

thanks in advance (: