Practice30Create account

Kabir drew (thick blue line) and (dashed orange line) on the same grid. The two graphs lie exactly on top of each other, and points A, B, C are marked on them. Which statement is correct?

Class 10Pair of Linear Equations in Two VariablesAlgebra — Systems of Equations
  • AThe pair has exactly three solutions: A, B and C
  • BThe pair has exactly one solution, B, where the line meets the -axis
  • CThe pair has no solution because only one line can be seen
  • DThe pair has infinitely many solutions: A, B, C and every other point of the line

Step-by-Step Solution

The lines coincide, so every point on the line satisfies both equations, e.g. and . Coincident lines give infinitely many solutions .
Answer: D) The pair has infinitely many solutions: A, B, C and every other point of the line

Key idea: Three geometric possibilities

Two lines in a plane can:

1. **Intersect at a single point** → exactly ONE solution. (Independent, consistent.)
2. **Be parallel and distinct** → NO solution. (Inconsistent.)
3. **Coincide (be the same line)** → INFINITELY many solutions. (Dependent, consistent.)

These three cases are decided by comparing the coefficient ratios:

| Condition on a₁/a₂, b₁/b₂, c₁/c₂ | Type | # solutions |
|---|---|---|
| a₁/a₂ ≠ b₁/b₂ | Lines intersect | One |
| a₁/a₂ = b₁/b₂ ≠ c₁/c₂ | Parallel | None |
| a₁/a₂ = b₁/b₂ = c₁/c₂ | Coincident | Infinitely many |

Master this chapter in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Pair of Linear Equations in Two Variables practice questions

More Class 10 Pair of Linear Equations in Two Variables practice

The lines x − y + 1 = 0 and 3x + 2y − 12 = 0 are drawn on the grid (1 square = 1 unit).…Lines ℓ₁ and ℓ₂ and the x-axis enclose the shaded triangle. Using the grid (1 square = 1…The dots mark where lines ℓ₁ and ℓ₂ cross the axes (1 square = 1 unit). Which pair of…The graph shows the fare of two taxi services in Pune for different distances. For what…The graph shows the monthly bill of two mobile plans for different numbers of call…