Mathematics · Vector Algebra

JEE Advanced 2025 — Paper 1 — Question 23

For any two points MM and NN in the XYX Y-plane, let MN→\overrightarrow{M N} denote the vector from MM to NN, and 0→\overrightarrow{0} denote the zero vector. Let P,QP, Q and RR be

three distinct points in the XYX Y-plane. Let SS be a point inside the triangle

△PQR\triangle P Q R such that SP→+5SQ→+6SR→=0→\overrightarrow{S P}+5 \overrightarrow{S Q}+6 \overrightarrow{S R}=\overrightarrow{0}

Let EE and FF be the mid-points of the

sides PRP R and QRQ R, respectively. Then the value of  length of the line segment EF length of the line segment ES\frac{\text { length of the line segment } E F}{\text { length of the line segment } E S} is \qquad

Answer: 1.2

Numerical answer — enter this value.

Step-by-step solution

∵SP→+5SQ→+6SR→=0→\because \overrightarrow{\mathrm{SP}}+5 \overrightarrow{\mathrm{SQ}}+6 \overrightarrow{\mathrm{SR}}=\overrightarrow{0}

(Let P.V. of P be p→,Q\overrightarrow{\mathrm{p}}, \mathrm{Q} be q→\overrightarrow{\mathrm{q}} and R be r→\overrightarrow{\mathrm{r}} )

⇒(p→−s→)+5(q→−s→)+6(r→−s→)=0→\Rightarrow(\overrightarrow{\mathrm{p}}-\overrightarrow{\mathrm{s}})+5(\overrightarrow{\mathrm{q}}-\overrightarrow{\mathrm{s}})+6(\overrightarrow{\mathrm{r}}-\overrightarrow{\mathrm{s}})=\overrightarrow{0}

⇒S⃗=p⃗+5q⃗+6r⃗12\Rightarrow \vec{S}=\frac{\vec{p}+5 \vec{q}+6 \vec{r}}{12}

⇒EF→=(q→−p→2)\Rightarrow \overrightarrow{\mathrm{EF}}=\left(\frac{\overrightarrow{\mathrm{q}}-\overrightarrow{\mathrm{p}}}{2}\right)

⇒ES→=(5q⃗−5p⃗12)=512(q⃗−p⃗)\Rightarrow \overrightarrow{E S}=\left(\frac{5 \vec{q}-5 \vec{p}}{12}\right)=\frac{5}{12}(\vec{q}-\vec{p})

∴∣EF→∣∣ES→∣=65=1.2\therefore \frac{|\overrightarrow{\mathrm{EF}}|}{|\overrightarrow{\mathrm{ES}}|}=\frac{6}{5}=1.2

Solution figure

Answer key and solution verified before publishing.

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Exam
JEE Advanced 2025
Paper
Paper 1
Subject
Mathematics
Chapter
Vector Algebra
Topic
Volume of parallelopiped, tetrahedron.
For any two points M and N in the X Y -plane, let overrightarrow M N… | JEE Advanced 2025 PYQ with Solution · DhiX AI