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JEE Mains · Maths · STD 12 - 10. vector algebra

Let \(\vec{a}=2 \hat{i}-3 \hat{j}+k, \vec{b}=3 \hat{i}+2 \hat{j}+5 k\) and a vector \(\vec{c}\) be such that \((\overrightarrow{\mathrm{a}}-\overrightarrow{\mathrm{c}}) \times \overrightarrow{\mathrm{b}}=-18 \hat{\mathrm{i}}-3 \hat{\mathrm{j}}+12 \mathrm{k}\) and \(\overrightarrow{\mathrm{a}} \cdot \overrightarrow{\mathrm{c}}=3\). If \(\overrightarrow{\mathrm{b}} \times \overrightarrow{\mathrm{c}}=\overrightarrow{\mathrm{d}}\), then \(|\overrightarrow{\mathrm{a}} \cdot \overrightarrow{\mathrm{d}}|\) is equal to :

  1. A \(18\)
  2. B \(12\)
  3. C \(9\)
  4. D \(15\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(15\)

Step-by-step Solution

Detailed explanation

\(\overrightarrow{\mathrm{a}}=2 \hat{\mathrm{i}}-3 \hat{\mathrm{j}}+\hat{\mathrm{k}}, \overrightarrow{\mathrm{b}}=3 \hat{\mathrm{i}}+2 \hat{\mathrm{j}}+5 \hat{\mathrm{k}}\)…