20 with a number minus what will equal 9. ^_^
Answer:
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.
PQ = 40 inches
The answer is C
add 15 to both sides:
subtract 6x from both sides:
Both sides are equal : true for all x
Answer D
hope this helps!