The sum of y and 20 is less than 37
1 answer:
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Answer:
P = 0.006
Step-by-step explanation:
Given
n = 25 Lamps
each with mean lifetime of 50 hours and standard deviation (SD) of 4 hours
Find probability that the lamp will be burning at end of 1300 hours period.
As we are not given that exact lamp, it means we have to find the probability where any of the lamp burning at the end of 1300 hours, So we have
Suppose i represents lamps
P (∑i from 1 to 25 ( > 1300)) = 1300
= P(>
) where
represents mean time of a single lamp
= P (Z> ) Z is the standard normal distribution which can be found by using the formula
Z = Mean Time () - Life time of each Lamp (50 hours)/ (SD/
)
Z = (52-50)/(4/) = 2.5
Now, P(Z>2.5) = 0.006 using the standard normal distribution table
Probability that a lamp will be burning at the end of 1300 hours period is 0.006
Answer:
The radius is 5 cm
Step-by-step explanation:
The formula for the area of a circle is :
To work out the length of the radius you would first need to divide the area of 78.5 cm by pi (pi=3.14), this gives you . This is because by dividing the area by pi we are isolating the value of the radius squared.
The final step is to work out the radius. You can do this by finding the square root of the radius squared which is 25, this gives you 5 cm. This means that the radius is 5 cm. This is because the square root is a number that when squared equals that number.
1) Divide 78.5 by pi.
2) Find the square root of 25 cm squared.
In this question pi is 3.14