High School

Select the correct answer.

A construction company is analyzing which of its older projects need renovation. Building B was built two years before Building C. Building D was built two years before Building B. The product of Building B's age and Building D's age is at least 195. If [tex]x[/tex] represents the age of Building C, which inequality represents this situation?

A. [tex]x^2 + 4 \geq 195[/tex]
B. [tex]x^2 + 8x + 16 \geq 195[/tex]
C. [tex]x^2 + 4x + 4 \geq 195[/tex]
D. [tex]x^2 + 6x + 8 \geq 195[/tex]

Answer :

To solve the problem, we need to establish the relationship between the ages of the buildings. Let's define the variable [tex]\( x \)[/tex] as the age of building C.

1. Determine the ages of buildings B and D:
- Building B was built 2 years before building C, so its age is [tex]\( x + 2 \)[/tex].
- Building D was built 2 years before building B, so its age is [tex]\( (x + 2) + 2 = x + 4 \)[/tex].

2. Set up the inequality based on the problem statement:
The problem states that the product of the ages of buildings B and D is at least 195. This can be expressed as:
[tex]\[
(x + 2)(x + 4) \geq 195
\][/tex]

3. Expand the expression:
To simplify and solve the inequality, we multiply the expressions:
[tex]\[
(x + 2)(x + 4) = x^2 + 4x + 2x + 8
\][/tex]
[tex]\[
= x^2 + 6x + 8
\][/tex]

4. Formulate the inequality:
We now have the expression:
[tex]\[
x^2 + 6x + 8 \geq 195
\][/tex]

Based on this reasoning, the correct inequality to represent the situation is [tex]\( x^2 + 6x + 8 \geq 195 \)[/tex], which corresponds to option D in the problem.