If the intensity of Marcelo's voice at the front of the class is 60dB. What will be the intensity of the sound a student will hear sitting in the last row of the lab, 10 meters from the front of the class in dB? What will need to be the intensity of the sound of Marcelo's voice in the front of the class to be heard in the back of the class - 10 meters from the front - with an intensity of 60 dB