Rank of matrix A=[1 2 −1; 0 1 7; 0 0 0] is:
- 1
- 2
- 3
- 4
Show answer and explanation
Answer: B. 2
Two nonzero rows remain ⇒ rank=2.
Practise 29 real Federal Board questions on Matrices and Determinants from 2023 to 2026. See the answer and explanation as soon as you answer.
Matrices and Determinants is one of the 14 main chapters in our Federal Board FSC Mathematics question bank (11th class), and about 6% of its real questions come from it. Tayyari Karo has 29 real questions on this chapter from 2023 to 2026; 10 are multiple choice and marked instantly, and the rest are short and long questions with a model answer. By difficulty: 14 medium, 9 hard, 6 easy.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
Rank of matrix A=[1 2 −1; 0 1 7; 0 0 0] is:
Answer: B. 2
Two nonzero rows remain ⇒ rank=2.
A consistent system MUST have at least:
Answer: A. At least one solution
Consistent means it has a solution — at least one.
If A is a 3×3 matrix, then |3A| results
Answer: D. 27|A|
|kA|=kⁿ|A| for n×n matrix; k=3, n=3 ⇒ 27|A|.
The system x+y+z=2, x+y+z=3, x+y+z=4 is:
Answer: B. Inconsistent
Same LHS with different constants ⇒ no solution ⇒ inconsistent.
If A is a matrix of order 3×2, then order of the product Aᵗ A is:
Answer: C. 2×2
Aᵗ is 2×3 and A is 3×2, so Aᵗ A has order (2×3)(3×2) = 2×2.
If det A = 5, what is the value of det(15A)? (where order of A is 2×2)
Answer: D. 1125
det(kA) = kⁿ det(A) for an n×n matrix. Here n = 2, so det(15A) = 15² × 5 = 225 × 5 = 1125.
Find the rank of matrix [1 2 3; 2 4 6; 1 1 1]
R₂→R₂−2R₁: [0 0 0]; R₃→R₃−R₁: [0 −1 −2]
Nonzero rows: [1 2 3] and [0 −1 −2]
Rank = 2
Find the value of k if the given system is consistent (has nontrivial solution): x−4y+3z=0, 2x+ky+z=0, x−2y+kz=0
For nontrivial solution, determinant must be zero:
|1 −4 3; 2 k 1; 1 −2 k| = (k²+2)+4(2k−1)+3(−4−k) = k²+5k−14 = 0
k = 2 or k = −7
| Session | Questions |
|---|---|
| 2026 Annual | 6 |
| 2025 1st Annual | 6 |
| 2025 2nd Annual | 6 |
| 2024 Annual | 6 |
| 2023 Annual | 5 |
29 real Federal Board (FBISE) Mathematics questions on Matrices and Determinants from 2023 to 2026, for 11th class. Each one shows the session it came from.
No. We could not find an official FBISE marking scheme for these papers, so the answers and explanations are written by Tayyari Karo for practice. Check anything important with your teacher or textbook.
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