Get Answers to all your Questions

header-bg qa

If the line 2x + y = k passes through the point which divides the line segment joining the points (1, 1) and (2, 4) in the ratio 3 : 2, then k equals

  • Option 1)

    \frac{29}{5}

  • Option 2)

    5

  • Option 3)

    6

  • Option 4)

    \frac{11}{5}

 

Answers (2)

best_answer

As learnt in

Selection formula -

x= \frac{mx_{2}+nx_{1}}{m+n}

y= \frac{my_{2}+ny_{1}}{m+n}

- wherein

If P(x,y) divides the line joining A(x1,y1) and B(x2,y2) in ration m:n

 

 

: A(1,1);B(2,4)

p(x_{1}y_{1})\: divides\: line \: segment\: \: AB\: in\: the\: ratio\: 3:2

x_{1}= \frac{3(2)+2(1)}{5}= \frac{8}{5}            y_{1}= \frac{3(4)+2(1)}{5}= \frac{14}{5}

2x+y=k\: \: passes\: through\: P(x_{1},y_{1})

\therefore 2\times \frac{8}{5}+\frac{14}{5}= k\Rightarrow k=6


Option 1)

\frac{29}{5}

This option is incorrect.

Option 2)

5

This option is incorrect.

Option 3)

6

Let that point be P  (x_1,y_1).

Then applying Section Formula -

If(x,y) P(x , y) divides the line joining A(x_{1}-y_{1}}})& B (x_{2}-y_{2}}})  in the ratio m : n, then ;

x=\frac{mx_{2}+nx_{1}}{m+n}          y=\frac{my_{2}+ny_{1}}{m+n}        

x_1=\dfrac{3*2+2*1}{5}= \dfrac{8}{5}

y_1=\dfrac{3*4+2*1}{5}= \dfrac{14}{5}

The point P lies on given line. So,

k=2x+y=2*\dfrac{8}{5}+\dfrac{14}{5}=\dfrac{30}{5}=6

This option is correct.

Option 4)

\frac{11}{5}

This option is incorrect.

Posted by

solutionqc

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE