Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Numerical Ability

Topic

Number System (1)

Question:

If $(a +b)^2 = 5 + 2\sqrt{6}$, what can be the possible value of ‘b’ from the following?

Options:

$\sqrt{7}$

$\sqrt{3}$

$\sqrt{6}$

5

Correct Answer:

$\sqrt{3}$

Explanation:

$(a +b)^2 = 5 + 2\sqrt{6}$

⇒ $(a +b)^2 = (2) + (3) + 2\sqrt{2×3}$

⇒ (a)2 + (b)2 + 2(a×b) = (\(\sqrt {2}\))2 + (\(\sqrt {3}\))2 + 2\(\sqrt {2×3}\)

⇒ a or b can be = $\sqrt{2}$ or $\sqrt{3}$

⇒ $(\sqrt{2}+\sqrt{3})^2=5 + 2\sqrt{6}$

Hence, $b=\sqrt{3}$