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
Answer:
1/2 L
Step-by-step explanation:
She makes 1 1/2 L of lemonade i.e. 3/2 L of lemonade.
She pours 1/4 of liter of lemonade into a thermos to take to the park. The amount of lemonade left is:
3/2 - 1/4 = 1 1/4 L = 5/4 L
Her brother drinks 2/5 of the remaining lemonade. The amount of lemonade that her brother drinks is:
2/5 * 5/4 = 1/2 L
Her brother drinks 1/2 L.
Hi there!
Using some simple conversions we can determine how many quarts are in 2 & a half gallons.
1 gallon = 4 quarts.
2 gallons = 8 quarts.
Since we're trying to determine how many quarts are in 2 & a half gallons we can separate our problem into how many quarts are in two gallons and how many are in a half a gallon.
2 gallons = 8 quarts.
.5 gallon = 2 quarts.
After adding this together we come up with the answer that there are 10 quarts in 2 & a half gallons. :)
Answer: b= -8
Step-by-step explanation: