If 45/k = 5, what is the value of k - 2? 6 7 9 11 38...

1. TRANSLATE the problem information

• Given equation: \(\frac{45}{k} = 5\)
• Find: the value of \(k - 2\) (not just k!)

2. INFER the solution strategy

• This is a two-step problem: first solve for k, then substitute that value into \(k - 2\)
• We need k before we can find \(k - 2\)

3. SIMPLIFY to solve for k

• Start with: \(\frac{45}{k} = 5\)
• Multiply both sides by k: \(45 = 5k\)
• Divide both sides by 5: \(k = 9\)

4. SIMPLIFY to find the final answer

• Substitute \(k = 9\) into the expression \(k - 2\)
• \(k - 2 = 9 - 2 = 7\)

Answer: B) 7

Why Students Usually Falter on This Problem

Most Common Error Path:

Weak INFER skill: Students solve correctly for \(k = 9\) but think this is the final answer and stop there.

They see \(k = 9\) and immediately select Choice C) (9) without realizing the problem asks for \(k - 2\), not k itself. This happens because they focus on solving the equation but don't carefully track what the question is actually asking for.

The Bottom Line:

This problem tests whether you can follow through on a multi-step question. The algebra is straightforward, but you must stay focused on what the question asks for - not just k, but \(k - 2\).