A, B and C are three matrices each of order 5; the order of matrix CA + B² is :

1. 5 × 4

2. 5 × 5

3. 4 × 5

4. 5 × 3

Let resultant matrix of CA be R.

C_{5 × 5} × A_{5 × 5} = R_{m × n}

We know that,

For matrix multiplication :

No. of columns in C must be equal to the number of rows in A.

Resultant matrix order = No. of rows in C × No. of columns in A.

∴ m = 5 and n = 5.

∴ Order of matrix R will be 5 × 5.

Let resultant matrix of B² be S.

B_{5 × 5} × B_{5 × 5} = S_{g × h}

Resultant matrix order = No. of rows in B × No. of columns in B.

∴ g = 5 and h = 5.

∴ Order of matrix S will be 5 × 5.

⇒ CA + B²

⇒ R + S

Addition of matrix possible between matrix of same order and same is the order of resultant matrix.

Hence, resultant matrix's order = 5 × 5

Hence, Option 2 is the correct option.