3x+4 combine like terms I think lol
Answer:
The standard deviation of the number of runs required is 2447.26
Step-by-step explanation:
For each run, there are only two possible outcomes. Either the program fails, or it does not. The probability of the computer failing during a run is independent of other runs. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The standard deviation for the expected number of trials for r sucesses is:

A computer program has a bug that causes it to fail once in every thousand runs, on average.
This means that 
In an effort to find the bug, independent runs of the program will be made until the program has failed six times. What is the standard deviation of the number of runs required?
This means that r = 6. So

The standard deviation of the number of runs required is 2447.26
See the attached diagram, it has all the information you need.
(a) If the green radii are all 1, then the orange diameters are all 2 + √2, so that the orange radii are (2 + √2)/2 = 1 + √2/2.
This is because we can join the radii of two adjacent green circles to form the sides of a square with side length equal to twice the radius - i.e. the diameter - of the green circles. The diagonal of any square occurs in a ratio to the side length of √2 to 1. Then we get the diameter of an orange circle by summing this diagonal length and two green radii, and hence the radius by dividing this by 2.
(b) We get the blue diameter in the same way. It has length (2 + √2) (1 + √2/2) = 3 + 2√2, so that the blue radius is (3 + 2√2)/2 = 3/2 + √2.
Answer:
180 or 90 degrees
Step-by-step explanation: