Answer:
0.9898 = 98.98% probability that there will not be more than one failure during a particular week.
Step-by-step explanation:
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

In which
x is the number of sucesses
e = 2.71828 is the Euler number
is the mean in the given interval.
3 failures every twenty weeks
This means that for 1 week, 
Calculate the probability that there will not be more than one failure during a particular week.
Probability of at most one failure, so:

Then



Then

0.9898 = 98.98% probability that there will not be more than one failure during a particular week.
Answer: square root of 10
Step-by-step explanation:
Answer:
60degrees
Step-by-step explanation
To get the angle x, you must first know that the sum of angle at a point is 360degrees. Hence;
x + <ADB + <CDB = 360
x +150 + 150 = 360
x+ 300 = 360
x = 360 - 300
x = 60
Hence the value of x is 60degrees
Answer:
The width of the building is 50 lamps and 60 lamps will be needed.
Step-by-step explanation:
The perimeter is computed by the sum of the sides of the building, since the length and width are equal on the oposite sides of the building, the perimeter is given by:
perimeter = 2*length + 2*width
900 = 2*(400) + 2*width
2*width + 800 = 900
2*width = 900 - 800
2*width = 100
width = 100/2 = 50 feets
To know how many lights bulbs will be needed we need to take the perimeter of the building and divide it by the space between the lamps. We have:
number o lamps = 900/15 = 60 lamps
This is a guess using logic, but my answer for this is that she concluded that she walked faster in the first 15 minutes. An increase in speed would increase the distance she walked in that amount of time