RonPurewal
A company makes a certain retirement package available to each employee starting on the anniversary of their hiring date when the sum of the employee’s age and the number of years she/he has worked for the company first equals or exceeds 91.
From the available options, select a possible age
at hiring and number of years after being hired for an employee on the date when this retirement package is
first made available to her/him. Make only two selections, one in each column.
Official Solution:First let’s investigate the required condition (age + years with the company ≥ 91) a little more closely. Every additional year worked by an employee increases
BOTH the employee’s age
AND years of experience by 1, so the sum of these will go up by 2 for each additional year worked. Accordingly,
the package becomes available when this sum becomes either 91 or 92. In other words, the required condition is
91 ≤ Current age + Years of experience ≤ 92
The variables in the columns, however, are not
current age and years of experience—they’re age
AT HIRE and years of experience. Let’s define variables for these: say the employee was a years old when hired, and has now worked y years for the company.
With these choices, the employee’s
CURRENT age is (a + y) years, and therefore we can write the required condition in terms of a and y:
91 ≤ (a + y) + y ≤ 92
91 ≤ a + 2y ≤ 92
If we solve this inequality for one of the variables, we’ll get a ‘formula’ into which we can plug the available numbers and get the workable values for the other variable. Solving for a is straightforward—just subtract 2y from each component of the inequality:
91 – 2y ≤ a ≤ 92 – 2y
We can now plug each of the five available values into this inequality for y, which will tell us the values of a that, together with that y-value, should solve the problem. Only one of those results should contain any of the other available values, and that pair of values will be our solution.
y (Years of exp) --- 91 – 2y ≤ a ≤ 92 – 2y (Range of a = Age at hire)
26 ------------------ 39 ≤ a ≤ 40
28 ------------------ 35 ≤ a ≤ 36
30 ------------------ 31 ≤ a ≤ 32
34 ------------------ 23 ≤ a ≤ 24
36 ------------------ 19 ≤ a ≤ 20
The second row contains the possibility a = 36, which is one of the available choices; none of the other possible ranges for
a contains any of the choices.
So, the solution is that unique possibility:
Age at Hire = 36,
Years after Hire Date = 28.