Answer:
b. The values X and Y are independent therefore, the mean is 34 seconds and the standard deviation is 50 seconds
Step-by-step explanation:
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
Before the training, the mean running time for the students to run a mile was 402 seconds with standard deviation 40 seconds.
This means that 
After completing the program, the mean running time for the students to run a mile was 368 seconds with standard deviation 30 seconds.
This means that 
Which of the following is true about the distribution of X-Y?
They are independent, so:


This means that the correct answer is given by option b.
Answer:
20
Step-by-step explanation:
Because 8 times 5 is 40, and if it is a triangle then it should be 20 because area as a triangle is base times height divided by two.
Answer:
b. Divide the quantity of output by the number of hours worked.
Step-by-step explanation:
<em>Since the ratio of the number of output to the number of hours worked shows the productivity. </em>
Thus, option (b) is correct.
Productivity is used to converting inputs into useful output. It measures the efficiency of a person, system, machine, factory, etc.
For Example: The employee who works less hours and assembled more radios has more productivity, that employee knows how to utilize time.
Answer:
20 and 16
Step-by-step explanation:
Let us find x and y.
x – y = 4 _____(1)
x/2 + y/2= 18___(2)
Multiply (2) by 2 and add to (1)
x - y = 4
+<u>(x + y = 36)</u>
<u>2x = 40</u>
=> x = 40 / 2 = 20
From (1):
20 - y = 4
=> y = 20 - 4 = 16
The two numbers are 20 and 16.