Question

Let $a,\vec{b},\vec{c}$ be vectors of length $3,4,5$ respectively. Let a be perpendicular to $\vec{b}+\vec{c},\vec{b}$ to $\vec{c}+\vec{a}\&$ $\vec{c}$ to $\vec{a}+\vec{b}$. Then $|\vec{a}+\vec{b}+\vec{c}|$ is :

• A. $2\sqrt{5}$
• B. $2\sqrt{2}$
• C. $10\sqrt{5}$
• D. $5\sqrt{2}$

Answer 1

Answer: (D)

Correct answer is (d) $5\sqrt{2}$