General Idea:
(i) Assign variable for the unknown that we need to find
(ii) Sketch a diagram to help us visualize the problem
(iii) Write the mathematical equation representing the description given.
(iv) Solve the equation by substitution method. Solving means finding the values of the variables which will make both the equation TRUE
Applying the concept:
Given: x represents the length of the pen and y represents the area of the doghouse
<u>Statement 1: </u>"The pen is 3 feet wider than it is long"

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<u>Statement 2: "He also built a doghouse to put in the pen which has a perimeter that is equal to the area of its base"</u>

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<u>Statement 3: "After putting the doghouse in the pen, he calculates that the dog will have 178 square feet of space to run around inside the pen."</u>

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<u>Statement 4: "The perimeter of the pen is 3 times greater than the perimeter of the doghouse."</u>

Conclusion:
The systems of equations that can be used to determine the length and width of the pen and the area of the doghouse is given in Option B.

This is something you would do through trial and error. At least, that's the approach I took. I'm not sure if there is any algorithm to solve. The solution I got is shown in the attached image below. There are probably other solutions possible. The trick is to keep each number separate but not too far away so that the other numbers to be filled in later don't get too crowded to their neighbor.
Side note: any mirror copy of what I posted would work as well since you can flip the page around and it's effectively the same solution.
Answer:
The expected value of lateness
hours.
Step-by-step explanation:
The probability distribution of lateness is as follows:
Lateness P (Lateness)
On Time 4/5
1 Hour Late 1/10
2 Hours Late 1/20
3 Hours Late 1/20
The formula of expected value of a random variable is:

Compute the expected value of lateness as follows:


Thus, the expected value of lateness
hours.