$[2$ points each$]$ Without a microphone, a certain singer in the concert hall produces $67$ dB $.$ With a microphone, this increases to $83\mathrm{.}5$ dB $.$

a$)$ The sound intensity with the microphone is how many times the previous $($unmiked$)$ intensity? Round your answer to the nearest $0\mathrm{.}1.$

b$)$ How many times as loud does the singer sound to the audience when using a microphone compared to without one? Round your answer to the nearest $0\mathrm{.}1.$