Class 10 Maths – Pair of Linear Equations in Two Variables MCQ

1. Which of the following pair of equations has a unique solution?

a) 2x + 3y = 7; 4x + 6y = 8
b) x + y = 4; 2x + 2y = 8
c) 3x – 2y = 1; 6x – 4y = 2
d) x – y = 1; x + y = 3

Answer:

d) x – y = 1; x + y = 3

Explanation:

The given lines have different slopes and hence they intersect at a unique point.

2. The system of equations x + y = 5 and 2x + 2y = 10 has:

a) No solution
b) Unique solution
c) Infinite solutions
d) Two solutions

Answer:

c) Infinite solutions

Explanation:

The second equation is just a multiple of the first. Thus, they represent the same line, leading to infinite solutions.

3. If the lines represented by the equations ax + by = c and bx – ay = 1 are perpendicular, then:

a) a^2 + b^2 = 0
b) ab = -1
c) a^2 – b^2 = 1
d) a^2 = b^2

Answer:

b) ab = -1

Explanation:

The product of the slopes of two perpendicular lines is -1.

4. The point of intersection of the lines 2x – y = 3 and x + y = 2 is:

a) (1, 1)
b) (2, 0)
c) (3, -1)
d) (0, 2)

Answer:

a) (1, 1)

Explanation:

On solving the two equations, we get x=1 and y=1.

5. The lines represented by the equations x – 2y = 3 and 2x – 4y = 6 are:

a) Parallel
b) Perpendicular
c) Coincident
d) Intersecting at a unique point

Answer:

c) Coincident

Explanation:

Both equations represent the same line.

6. The condition for the equations ax + by = c and bx + ay = d to represent coincident lines is:

a) a/b = c/d
b) a/c = b/d
c) a/b = d/c
d) c/d = a/b

Answer:

c) a/b = d/c

Explanation:

For coincident lines, the ratios of coefficients should be equal.

7. The solution to the system of equations x – y = 4 and x + y = 2 is:

a) (3, -1)
b) (-1, 3)
c) (3, 1)
d) No solution

Answer:

a) (3, -1)

Explanation:

Solving the equations simultaneously, we get x = 3 and y = -1.

8. Which of the following pairs of equations are parallel?

a) 2x + 3y = 5; 4x + 6y = 7
b) x – y = 1; x + y = 1
c) 3x + 4y = 7; 6x + 8y = 14
d) x + y = 4; 2x + 3y = 8

Answer:

a) 2x + 3y = 5; 4x + 6y = 7

Explanation:

The lines have the same slope but different y-intercepts, hence they are parallel.

9. If a system of two equations has a unique solution, then the lines are:

a) Coincident
b) Parallel
c) Intersecting at a unique point
d) Both a and b

Answer:

c) Intersecting at a unique point

Explanation:

If there's a unique solution, the two lines intersect at just one point.

10. The system of equations 2x – y = 3 and 4x – 2y = 6 has:

a) No solution
b) One solution
c) Infinite solutions
d) Two solutions

Answer:

a) No solution

Explanation:

Both equations represent parallel lines as they have the same slope.

11. The graph of the equation 3x – 4y = 12 intersects the x-axis at:

a) (4, 0)
b) (0, 3)
c) (-4, 0)
d) (0, -3)

Answer:

a) (4, 0)

Explanation:

Setting y = 0 in the equation, we get x = 4.

12. The solution to the system of equations x + y = 5 and x – y = 1 is:

a) (3, 2)
b) (2, 3)
c) (1, 4)
d) No solution

Answer:

a) (3, 2)

Explanation:

Solving the equations simultaneously, we get x = 3 and y = 2.

13. If the lines represented by the equations 2x + 3y = 5 and ax + by = 7 are parallel, then:

a) a/b = 2/3
b) b/a = 2/3
c) a + b = 5
d) a = 2 and b = 3

Answer:

a) a/b = 2/3

Explanation:

Parallel lines have the same slope. Thus, a/b should be equal to the ratio of the coefficients of x and y in the first equation.

14. If the pair of equations x – y = 2 and cx – dy = 2 has no solution, then:

a) c/d = 1
b) d/c = 1
c) c = d
d) c + d = 1

Answer:

a) c/d = 1

Explanation:

For no solution, the lines should be parallel. Thus, the ratio of coefficients should be the same.

15. The system of equations 3x – 2y = 8 and 6x – 4y = 16 has:

a) No solution
b) One solution
c) Infinite solutions
d) Two solutions

Answer:

c) Infinite solutions

Explanation:

Both equations represent the same line, leading to infinite solutions.

16. The condition for the lines 3x – 5y = 7 and kx – 5y = 14 to be parallel is:

a) k = 6
b) k = 3
c) k = 7
d) k = 14

Answer:

a) k = 6

Explanation:

The lines are parallel if they have the same slope. Thus, k should be 6 to maintain the same ratio of x and y coefficients.

17. The graph of the equation y = 3 intersects the x-axis at:

a) (0, 3)
b) (3, 0)
c) (0, -3)
d) Does not intersect

Answer:

d) Does not intersect

Explanation:

The equation represents a horizontal line passing through the point (0,3). It doesn't intersect the x-axis.

18. The solution of the pair of equations 2x + y = 7 and x – 2y = 3 is:

a) (2, 3)
b) (3, 1)
c) (2, 1)
d) (1, 2)

Answer:

b) (3, 1)

Explanation:

Solving the equations simultaneously, we get x = 3 and y = 1.

19. If the pair of equations 2x + 3y = 6 and 4x + ky = 8 has a unique solution, then k is not equal to:

a) 6
b) 3/2
c) 2
d) 8

Answer:

b) 3/2

Explanation:

For a unique solution, the lines should not be parallel. Therefore, k should not equal the ratio of coefficients from the first equation.

20. The pair of equations y = x and y = -x represents lines that are:

a) Parallel
b) Coincident
c) Perpendicular
d) Neither parallel nor perpendicular

Answer:

c) Perpendicular

Explanation:

The lines y = x and y = -x have slopes that are negative reciprocals of each other, hence they are perpendicular.

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