JEE Main · MathematicsEasy

$If the magnitude of a vector a is 5, what is the magnitude of 3 a ?$

A. $5$
B. $8$
C. $15$
D. $25$

Show correct answer & step-by-step solution

Correct answer: C — $15$

Solution

The magnitude ∣ k a ∣ = ∣ k ∣∣ a ∣ . Given ∣ a ∣ = 5 and k = 3, we have ∣3 a ∣ = 3 \times 5 = 15 .

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