Answer:
it will take a programmer about 16.67 times to work before they are fired
Step-by-step explanation:
From the information given;
The transistion matrix for this study can be computed as:
P M X
P 0.7 0.2 0.1
M 0 0.95 0.05
X 0 0 1
where;
The probability that the programmer remains a programmer = 
The probability that the programmer turns out to be a manager = 
The probability that the programmer is being fired = 
Thus, the required number of years prior to the moment being fired for an employee y(P), for programmer and y(M) for manager is represented by ;



y(M) = 
y(M) =20
y(P)=1+0.7y(P)+0.2y(M)
y(P) - 0.7y(P) = 1 + 0.2y(M)
0.3y(P) = 1 + 0.2(20)=1+4
0.3y(P) = 1 + 4
0.3y(P) = 5


Therefore, it will take a programmer about 16.67 times to work before they are fired
This is the same a taking away 6% so you can say:
72000(100-6)/100
72000(94/100)
72000(0.94)
$67,680
There are additional details to the problem that you have left out. I have found them in other resources. The tray has to be 3 centimeters high and the length is five centimeters longer than its width. The volume of the tray is 252 cubic centimeters.
With these given, we can find the equation with the width alone as the variable:



To know if it's possible for the width to be 7.5 centimeters, we just plug this as the value of x and see if it satisfies the equation:



As we can see, the equation was not satisfied therefore it is NOT possible for the width to be 7.5 centimeters.