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UI Post-UTME Mathematics 2025 (Model questions) Question 21

Question 21

Coordinate Geometry

Find the value of k if the points (1, 2), (3, 5), (k, 8) are collinear

  1. A.5
  2. B.4
  3. C.6
  4. D.7
Show the answer and explanation

Answer: A (5)

Explanation

Gradient from (1, 2) to (3, 5) is 3/2; from (3, 5) to (k, 8) it is 3/(k − 3). Equal gradients give k − 3 = 2, so k = 5.