Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If 8K6 + 15K3 - 2 = 0

Find K + \(\frac{1}{K}\) (positive value)

Options:

2\(\frac{1}{2}\)

\(\frac{5}{4}\)

\(\frac{3}{7}\)

2

Correct Answer:

2\(\frac{1}{2}\)

Explanation:

Formula → 15K3 = 16K3 - K3 

 

8K6 + 16K3 - K3 - 2 = 0

8K3 (K3 + 2) - 1 (K3 + 2)= 0

K3 = \(\frac{1}{8}\) or K3 = -2

So if, K3 = \(\frac{1}{8}\) → K = \(\sqrt [3]{\frac{1}{8}}\) = \(\frac{1}{2}\)

⇒ K + \(\frac{1}{K}\) = \(\frac{1}{2}\) + 2 = \(\frac{5}{2}\) or 2\(\frac{1}{2}\)