Speed was increased 20% to 48 mph. What was the speed before the increase

The decibel level of sound is 50 db greater on a busy street than in a quiet room where the intensity of sound is watt/m2. the level of sound in the quiet room is db, and the intensity of sound in the busy street is watt/m2. use the formula , where is the sound level in decibels, i is the intensity of sound, and is the smallest sound intensity that can be heard by the human ear (roughly equal to watts/m2).

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

Using the side-splitter theorem, daniel wrote a proportion for the segment formed by luke segment de. what is ec?