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Jee Main 2025Medium JEE math MCQ

Let the position vectors of the vertices $A, B$ and $C$ of a tetrahedron $ABCD$ be $\mathbf{i} + 2\mathbf{j} + \mathbf{k}, \mathbf{i} + 3\mathbf{j} = 2\hat{k}$ and $2\mathbf{i} + \mathbf{j} - \mathbf{k}$ respectively. The altitude from the vertex $D$ to the opposite face $ABC$ meets the median line segment through $A$ of the triangle $ABC$ at the point $E$. If the length of $AD$ is $\frac{\sqrt{11}}{3}$ and the volume of the tetrahedron is $\frac{\sqrt{805}}{6}$, then the position vector of $E$ is
  1. A. $\frac{1}{3}(7\mathbf{i} + 4\mathbf{j} + 3\mathbf{k})$ -
  2. B. $\frac{1}{3}(i + 4\mathbf{j} + 7\mathbf{k})$ -
  3. C. $\frac{1}{3}(12\mathbf{i} + 12\mathbf{j} + \mathbf{k})$ -
  4. D. $\frac{1}{3}(7\mathbf{i} + 12\mathbf{j} + \mathbf{k})$

Solution

The correct option is **D**. (D. $\frac{1}{3}(7\mathbf{i} + 12\mathbf{j} + \mathbf{k})$)

MATH

mediumPYQ Reworded
Question
Read carefully, then pick the best option.
Let the position vectors of the vertices A,BA, B and CC of a tetrahedron ABCDABCD be i+2j+k,i+3j=2k^\mathbf{i} + 2\mathbf{j} + \mathbf{k}, \mathbf{i} + 3\mathbf{j} = 2\hat{k} and 2i+jk2\mathbf{i} + \mathbf{j} - \mathbf{k} respectively. The altitude from the vertex DD to the opposite face ABCABC meets the median line segment through AA of the triangle ABCABC at the point EE. If the length of ADAD is 113\frac{\sqrt{11}}{3} and the volume of the tetrahedron is 8056\frac{\sqrt{805}}{6}, then the position vector of EE is
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Jee Main 2025 — Medium JEE Mathematics MCQ | MyGoalPrep