Sound Intensity Question

Tiba

1. The problem statement, all variables and given/known data

A choir made up by 100 voices (i.e. 100 singers), during the execution of a song, reaches the sound intensity of 100dB. Assuming that all singers sang with the same intensity, the sound intensity of each singer was...?


2. Relevant equations

ΔS=10.log(I/Io)

3. The attempt at a solution

The correct answer is 80, but I REALLY have no clue on how to get it!

voko

What is I and what is Io here?