Question

For which of the following elements in the determinant Δ=\(\begin{vmatrix}2&8\\4&7\end{vmatrix}\), the minor of the element is 2?

(a) 2

(b) 7

(c) 4

(d) 8

I had been asked this question in a job interview.

My enquiry is from Determinants topic in portion Determinants of Mathematics – Class 12

Answer 1

The correct answer is (b) 7

Explanation: Consider the element 7 in the determinant Δ=\(\begin{vmatrix}2&8\\4&7\end{vmatrix}\)

The minor of the element 7 can be obtained by deleting R2 and C2

∴M22=2

Hence, the minor of the element 7 is 2.