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
 > 1300)) = 1300 
= P( >
>  )                  where
)                  where  represents mean time of a single lamp
 represents mean time of a single lamp
= P (Z>  )                Z is the standard normal distribution which can be found by using the formula
)                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/
) - Life time of each Lamp (50 hours)/ (SD/ )
)
Z = (52-50)/(4/ ) = 2.5
) = 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:
a
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer: 6 days
Explanation: If he washes 75 cars in 5 days; and you need to find how many days it takes to wash 90 you do 75 divided by 5 which is 15; so he washes 15 cars in a day, then do 90 divided by 15 which is 6 days
        
             
        
        
        
<u>Given:</u>
It is given that the ridge is 360 inches tall. 
<u>Assumptions:</u>
Assume you are 170.1 cm tall which equals 67 inches tall, the height from your eye to the floor is  inches.
 inches.
The distance from your eye level to the bottom of the ridge is 427 inches.
Assume the angle A is 60°.
<u>To find the distance from you to your dog.</u>
<u>Solution:</u>
A right-angled triangle can be formed where the angle is 60°, the distance between you and the dog is the hypotenuse of the triangle and your height from the floor is the adjacent side of the triangle.
Assume the hypotenuse of the triangle measures x inches.
To determine the length of the hypotenuse, we determine the cos of the angle.



So if the ridge is 360 inches tall and you are 67 inches tall and the angle A is 60°, the distance between your dog and you is 854 inches.
 
        
             
        
        
        
Answer:
B
Step-by-step explanation:
In a parellelogram opposite angles are always equal