SSC Sample Paper Mock Test-16 SSC CGL Tear-II Paper-1

  • question_answer
    If the points A (2, 3), B (5, k) and C (6, 7) are collinear, then k =?

    A)  \[4\]

    B)  \[6\]

    C)  \[\frac{-\,\,3}{2}\]        

    D)  \[\frac{11}{4}\]

    Correct Answer: B

    Solution :

    Here      \[{{x}_{1}}=2,\]\[{{x}_{2}}=5,\]\[{{x}_{3}}=6,\]\[{{y}_{1}}=3,\]\[{{y}_{2}}=k\]and \[{{y}_{3}}=7.\] \[\Delta =0\]\[\Leftrightarrow \]\[\frac{1}{2}\cdot \{{{x}_{1}}({{y}_{2}}-{{y}_{3}})+{{x}_{2}}({{y}_{3}}-{{y}_{1}})+{{x}_{3}}({{y}_{1}}-{{y}_{2}})\}\]\[=0\] \[\Leftrightarrow \]\[2\,\,(k-7)+5\,\,(7-3)+6\,\,(3-k)=0\]\[\Leftrightarrow \]\[4k-24\]\[\Leftrightarrow \]\[k=6\]


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