The formula to calculate standard deviation from probability is \sqrt(n*p*(1-p)). n is the sample size, and 200 in this case (number of putts for practice). p is 80% or 0.8, the probability that he can make it. So the standard deviation is \sqrt(200*0.8*(1-0.8)=\sqrt(200*0.8*0.2)=\sqrt(16)=4.
Answer:
There must be 96 milk chocolates.
Step-by-step explanation:
If you take the original ratio, 5:12, and replace the 5 with 40, you'd discover that 40 divided by 5 is 8. So what do you do? You multiply the 12 by 8 to get 96 so now the ratio is 40:96.