3. Between 2011 and 2021, the annual average ph of precipitation in a northern Ontario PH = - log [H+] town dropped from 5.6 to 4.3. How many times more acidic was the precipitation in 2021 than the precipitation in 2011? Hint: Some useful equations are provided. [3A] B2 - B1 = 10 log- M = 108 To 4. Students participating in a psychology experiment, and taking MHF4U, were given an exam. Every month, the students were retested to see how much of the material they remembered. The average scores (as a percentage) for the group are given by the human memory model: 66log, (t+1) f (t) = 72 - - 5 where t is time in months 0