Each dial has 4 letters and only one of them is correct; the probability to choose the correct one is then 1/4. Selecting a letter in each dial is independent, then the probability of guessing the right combination in one try is 1/4 * 1/4 * 1/4 = 1/64
8% means a probability of 8/100 or an odds of 8 in 100. Dividing each term by 8 we get 8/8 = 1 in 100/8 = 12.5, which can be rounded to 1 in 12
80% means a probability of 80/100 = 0.8. Given that the 2 free-throws are independent, the probability that he makes both is 0.8*0.8 = 0.64 or 64%
