18) [2 points each] Without a microphone, a certain singer in the concert hall produces 67 dB. With a microphone, this increases to 79.5 dB. a) The sound intensity with the microphone is how many times the previous (unmiked) intensity? Round your answer to the nearest 0.1. b) How many times as loud does the singer sound to the audience when using a micrphone compared to without one? Round your answer to the nearest 0.1