The marks obtained by three students P, Q and R in four subjects are written as the matrix
\(A = \begin{bmatrix}78&65&90&82\\70&88&76&91\\85&72&68&80\end{bmatrix}\),
where the rows are for P, Q and R in that order and the columns are for English, Hindi, Maths and Science in that order. The element \(a_{23}\) of A is the marks of
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → student Q in Maths
In \(a_{ij}\), the first suffix i is the row and the second suffix j is the column.
\(a_{23}\): row 2, column 3
Row 2 is for student Q and column 3 is for Maths, so \(a_{23} = 76\) is the marks of student Q in Maths.
Why the other options are incorrect
Option (1) student R in Hindi — Incorrect. That is row 3, column 2, the element \(a_{32} = 72\); the suffixes are taken in the wrong order.
Option (3) student Q in Hindi — Incorrect. That is the element \(a_{22} = 88\).
Option (4) student R in Maths — Incorrect. That is the element \(a_{33} = 68\).