Answer:
a) 40.13% probability that a laptop computer can be assembled at this plant in a period of time of less than 19.5 hours.
b) 34.13% probability that a laptop computer can be assembled at this plant in a period of time between 20 hours and 22 hours.
Step-by-step explanation:
When the distribution is normal, we use the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this question:

a)Less than 19.5 hours?
This is the pvalue of Z when X = 19.5. So



has a pvalue of 0.4013.
40.13% probability that a laptop computer can be assembled at this plant in a period of time of less than 19.5 hours.
b)Between 20 hours and 22 hours?
This is the pvalue of Z when X = 22 subtracted by the pvalue of Z when X = 20. So
X = 22



has a pvalue of 0.8413
X = 20



has a pvalue of 0.5
0.8413 - 0.5 = 0.3413
34.13% probability that a laptop computer can be assembled at this plant in a period of time between 20 hours and 22 hours.
Answer:
a) 
b) 
c) 
Step-by-step explanation:
For total cost function
, average cost is given by
i.e., total cost divided by number of units produced.
Marginal average cost function refers to derivative of the average cost function i.e., 
Given:
Average cost = 
a)
At x = 50 units,

b)
Average cost = 
c)
Marginal average cost:
Differentiate average cost with respect to 
Take 
using quotient rule, 
Therefore,

Answer:
4Joules
Step-by-step explanation:
According to Hooke's law which states that extension of an elastic material is directly proportional to the applied force provide that the elastic limit is not exceeded. Mathematically,
F = ke where
F is the applied force
K is the elastic constant
e is the extension
If a spring exerts a force of 6 N when stretched 3 m beyond its natural length, its elastic constant 'k'
can be gotten using k = f/e where
F = 6N, e = 3m
K = 6N/3m
K = 2N/m
Work done on an elastic string is calculated using 1/2ke².
If the spring is stretched 2 m beyond its natural length, the work done on the spring will be;
1/2× 2× (2)²
= 4Joules