JEE Main & Advanced Sample Paper JEE Main Sample Paper-47

  • question_answer
    Direction: For the following questions, chose the correct answer from the codes [a], [b] [c] and [d] defined as follows.
    Let there are three points P, Q and R having position vectors a, b and c, respectively.
    Statement I If \[2a+3b-5c=0\], then points P, Q and R must be collinear.
    Statement II For three points A, B and C; \[AB=\lambda AC,\] then the points A, B and C must be collinear.

    A)  Statement I is true, Statement II is also true and Statement II is the correct explanation of Statement I.

    B)  Statement I is true, Statement II is true and Statement II is not the correct explanation of Statement I.

    C)  Statement I is true, Statement II is false.

    D)  Statement I is false, Statement II is true.

    Correct Answer: A

    Solution :

     I. \[OP=a,\,\,OQ=b,\,\,OR=c\] Given, \[2a+3b-5c=0\] \[\Rightarrow \]            \[3(b-a)+5(a-c)=0\] \[\Rightarrow \]            \[3(OQ-OP)=5(OR-OP)\] \[\Rightarrow \]            \[3PQ=5PR\] \[\Rightarrow \]            \[PQ=\frac{5}{3}PR\] P, Q and R are collinear.


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