Which of the statements is sufficient to answer the question?
Question:
Find the value of n.
Statements:
1)
2)
3) A + B = O, where O is a null matrix of 2 × 2

Question

Question

This question was previously asked in

RRC Group D Previous Paper 17 (Held On: 27 Nov 2018 Shift 2)

Answer 1

Concept:

Let A and B be any two matrices of same order m × n, then their sum A + B = [a_ij + b_ij]_{m × n} where A = [a_ij]_{m × n} and B = [b_ij]_{m × n}

Calculation:

From statement 1∶

We can not find anything with this statement.

From statement 2∶

We cannot find anything with this statement.

From statement 3∶

A + B = O, where O is a null matrix of 2 × 2.

We cannot find anything with this statement.

Combining all these statements∶

∵ O is a null matrix.

A + B = O

⇒ n + 1 = 0

∴ n = -1