ECAT — Engineering College Admission Test (UET)

ECAT Mathematics — Straight Lines and Linear Programming (Set 5)

Take the ECAT Mathematics — Straight Lines and Linear Programming (Set 5): 30 multiple-choice questions (40 minutes) with instant scoring and a full…

What this test covers

Sample questions with answers

The first 5 questions of this test, with the correct answer and explanation.

  1. Q1. The point on the y-axis that is equidistant from (2, 0) and (0, 4) is:

    • A. (0, 1)
    • B. (0, 2)
    • C. (0, 3)
    • D. (0, 3/2) ✓

    Answer: D. (0, 3/2)

    Explanation: For (0, k): 4 + k² = (k − 4)², so 4 = −8k + 16 and k = 3/2.

  2. Q2. The equation x² − y² + 2x + 1 = 0 represents two lines meeting at:

    • A. (−1, 0) ✓
    • B. (0, −1)
    • C. (1, 0)
    • D. (0, 1)

    Answer: A. (−1, 0)

    Explanation: (x + 1)² = y², so x + 1 = ±y, i.e. x − y + 1 = 0 and x + y + 1 = 0. They meet where y = 0, x = −1.

  3. Q3. The slope of the bisector of the acute angle between the x-axis and the line 4y = 3x is:

    • A. 3/8
    • B. 1/3 ✓
    • C. 2/3
    • D. 1/2

    Answer: B. 1/3

    Explanation: If tan θ = 3/4 (cos θ = 4/5), tan(θ/2) = sin θ/(1 + cos θ) = (3/5)/(9/5) = 1/3.

  4. Q4. The line through the intersection of x + y = 4 and x − y = 2 and parallel to 2x + 3y = 1 is:

    • A. 3x − 2y = 7
    • B. 2x + 3y = 9 ✓
    • C. 2x + 3y = 7
    • D. 2x + 3y = 11

    Answer: B. 2x + 3y = 9

    Explanation: The lines meet at (3, 1). A parallel line is 2x + 3y = c with c = 6 + 3 = 9.

  5. Q5. In triangle OBC with O(0, 0), B(4, 0), C(1, 3), the altitude from O to side BC has length:

    • A. 3
    • B. 4
    • C. √10
    • D. 2√2 ✓

    Answer: D. 2√2

    Explanation: BC has slope −1, so its line is x + y = 4. Distance from the origin: 4/√2 = 2√2.

The other 25 questions

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  1. Q6. The orthocentre of the triangle with vertices (0, 0), (4, 0) and (1, 3) is:

    • A. (1, 1)
    • B. (2, 1)
    • C. (1, 3)
    • D. (5/3, 1)
  2. Q7. The circumcentre of the triangle with vertices (0, 0), (6, 0) and (2, 4) is:

    • A. (3, 1)
    • B. (8/3, 4/3)
    • C. (2, 1)
    • D. (3, 2)
  3. Q8. A line through (4, 3) has non-zero intercepts, and its x-intercept is twice its y-intercept. Its equation is:

    • A. x + 2y = 8
    • B. x + 2y = 6
    • C. 2x + y = 11
    • D. x + 2y = 10
  4. Q9. The area of the quadrilateral with vertices (0, 0), (4, 0), (5, 3) and (1, 5), taken in that order, is:

    • A. 34
    • B. 14
    • C. 17
    • D. 16
  5. Q10. The slope of a line inclined at 105° to the positive x-axis is:

    • A. −(2 + √3)
    • B. 2 + √3
    • C. −(2 − √3)
    • D. 2 − √3
  6. Q11. Eliminating t from x = 2 + 3t, y = 1 + 4t gives the line:

    • A. 4x − 3y = 5
    • B. 4x − 3y = 11
    • C. 3x − 4y = 2
    • D. 4x + 3y = 11
  7. Q12. The origin is shifted to (2, −1) without rotating the axes. The new coordinates of the point (5, 3) are:

    • A. (3, 2)
    • B. (−3, −4)
    • C. (3, 4)
    • D. (7, 2)
  8. Q13. The origin is shifted to (1, −1). The line 2x − y = 3 then has equation:

    • A. 2X − Y = 6
    • B. 2X − Y = −3
    • C. 2X − Y = 0
    • D. 2X − Y = 3
  9. Q14. Axes are rotated anticlockwise through 90° (X = x cos θ + y sin θ, Y = −x sin θ + y cos θ). The point (3, 2) then has coordinates:

    • A. (3, −2)
    • B. (−3, 2)
    • C. (−2, 3)
    • D. (2, −3)
  10. Q15. The axes are rotated through 45° (anticlockwise). The equation xy = 8 becomes:

    • A. X² − Y² = 4
    • B. X² − Y² = 8
    • C. X² + Y² = 16
    • D. X² − Y² = 16
  11. Q16. The equation x² + kxy + 9y² = 0 represents coincident lines when k equals:

    • A. only 6
    • B. ±9
    • C. ±3
    • D. ±6
  12. Q17. For the lines given by 3x² + 10xy + 3y² = 0, the tangent of the acute angle between them is:

    • A. 1/3
    • B. 3/4
    • C. 4/3
    • D. 8/3
  13. Q18. Maximise z = 3x + 5y subject to x ≤ 4, y ≤ 6, 3x + 2y ≤ 18, x, y ≥ 0. The maximum value of z is:

    • A. 36
    • B. 30
    • C. 38
    • D. 27
  14. Q19. A workshop makes chairs (x) and tables (y) with profits of Rs 40 and Rs 50. Carpentry time is 2x + 3y ≤ 120 hours and x + y ≤ 50 (finishing). The maximum profit is:

    • A. Rs 2400
    • B. Rs 2000
    • C. Rs 2200
    • D. Rs 2250
  15. Q20. Minimise z = 4x + 6y subject to 2x + y ≥ 10, x + 3y ≥ 15, x, y ≥ 0. The minimum value of z is:

    • A. 30
    • B. 36
    • C. 60
    • D. 40
  16. Q21. For the problem: maximise z = x + y subject to x − y ≤ 1, x ≥ 0, y ≥ 0, which statement is correct?

    • A. z has maximum value 2
    • B. the feasible region is empty
    • C. z has no maximum value
    • D. z has maximum value 1
  17. Q22. Maximise z = 3x + 6y subject to x + 2y ≤ 10, x ≤ 8, x, y ≥ 0. The maximum value 30 is attained:

    • A. at the single corner point (8, 1) and nowhere else on the feasible region
    • B. at the single corner point (0, 5) and nowhere else on the feasible region
    • C. at every point of the edge joining (0, 5) and (8, 1)
    • D. at the single corner point (8, 0) and nowhere else on the feasible region
  18. Q23. The region 1 ≤ x ≤ 4, 0 ≤ y ≤ x is bounded by four lines. Its area in square units is:

    • A. 9
    • B. 8
    • C. 15/2
    • D. 15/4
  19. Q24. Maximise z = 5x + 3y subject to x + y ≤ 6, 2x + y ≤ 10, x, y ≥ 0. The maximum value of z is:

    • A. 26
    • B. 18
    • C. 30
    • D. 25
  20. Q25. Maximise z = x + y subject to x + y ≤ 2, x + y ≥ 5, x, y ≥ 0. Which statement is correct?

    • A. the maximum is 2
    • B. the maximum is 5
    • C. z is unbounded
    • D. there is no feasible solution
  21. Q26. The median from A(0, 0) of the triangle with vertices A(0, 0), B(4, 2) and C(2, 6) has equation:

    • A. 3x − 4y = 0
    • B. 2x − y = 0
    • C. x − y = 0
    • D. 4x − 3y = 0
  22. Q27. A point P moves so that PA² − PB² = 16, where A = (0, 0) and B = (4, 0). The locus of P is the line:

    • A. x = 4
    • B. x = 2
    • C. x = 8
    • D. y = 4
  23. Q28. The points on the line y = x that are at distance √2 from the line x + y = 2 are:

    • A. (−1, −1) and (3, 3)
    • B. (0, 0) and (2, 2)
    • C. (1, 1) and (2, 2)
    • D. (0, 0) and (1, 1)
  24. Q29. For every real k, the line kx − y + 3 − 2k = 0 passes through the fixed point:

    • A. (3, 2)
    • B. (0, 3)
    • C. (−2, 3)
    • D. (2, 3)
  25. Q30. The distance of the origin from the line x/3 + y/4 = 1 is:

    • A. 5/12
    • B. 7/5
    • C. 12/5
    • D. 12/7