Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Algebra

Question:

An even number is the determinant of

(A) $\left[\begin{array}{rr}1 & -1 \\ -1 & 5\end{array}\right]$

(B) $\left[\begin{array}{cc}13 & -1 \\ -1 & 15\end{array}\right]$

(C) $\left[\begin{array}{rr}16 & -1 \\ -11 & 15\end{array}\right]$

(D) $\left[\begin{array}{rr}6 & -12 \\ 11 & 15\end{array}\right]$

Choose the correct answer from the options given below:

Options:

(A), (B) and (D) only

(A), (B) and (C) only

(A), (B), (C) and (D)

(B), (C) and (D) only

Correct Answer:

(A), (B) and (D) only

Explanation:

The correct answer is Option (1) → (A), (B) and (D) only

$(A)\;\begin{vmatrix}1&-1\\-1&5\end{vmatrix}=1\cdot5-(-1)(-1)=5-1=4.$

$(B)\;\begin{vmatrix}13&-1\\-1&15\end{vmatrix}=13\cdot15-1=195-1=194.$

$(C)\;\begin{vmatrix}16&-1\\-11&15\end{vmatrix}=16\cdot15-(-1)(-11)=240-11=229.$

$(D)\;\begin{vmatrix}6&-12\\11&15\end{vmatrix}=6\cdot15-(-12)(11)=90+132=222.$

$\text{Even determinants are }4,194,222.$

$\text{Correct options: (A),(B),(D).}$