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TS EAMCET · Maths · Permutation Combination

Out of thirty points in a plane, eight of them are collinear. The number of straight lines that can be formed by joining these points, is

  1. A \(296\)
  2. B \(540\)
  3. C \(408\)
  4. D \(348\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(408\)

Step-by-step Solution

Detailed explanation

Total number of points in a plane is 30 . Out of them, 8 points are collinear. \(\therefore\) Total number of straight lines formed \[ \begin{aligned} & ={ }^{30} C_2-{ }^8 C_2+1 \\ & =\frac{30 \times 29}{2}-\frac{8 \times 7}{2 \times 1}+1 \\ & =435-28+1=408 \end{aligned} \]