Inverse of matrix - Jamb Mathematics Past Questions and Answers

Question 1:

• JAMB 1979

The mean of the numbers 1.2, 1.0, 0.9, 1.4, 0.8, 0.8, 1.2 and 1.1 is

A. 1.5
B. 0.8
C. 1.0
D. 1.02
E. 1.05

Question 2:

• JAMB 2019

Given the matrix \(A = \begin{vmatrix} 3 & -2 \\ 1 & 6 \end{vmatrix}\). Find the inverse of matrix A.

A. \(\begin{vmatrix} 6 & 2 \\ 1 & 6 \end{vmatrix}\)
B. \(\begin{vmatrix} \frac{2}{11} & \frac{1}{12}\\ \frac{3}{20} & \frac{1}{10} \end{vmatrix}\)
C. \(\begin{vmatrix} -3 & 2 \\ -1 & -6 \end{vmatrix}\)
D. \(\begin{vmatrix} \frac{3}{10} & \frac{1}{10} \\ \frac{-1}{20} & \frac{3}{20}\end{vmatrix}\)

Question 3:

• JAMB 2011

The inverse of matrix N = \(\begin{vmatrix} 2 & 3 \\
1 & 4\end{vmatrix}\) is

A. \(\frac{1}{5}\) \(\begin{vmatrix} 2 & 1 \\ 3 & 4\end{vmatrix}\)
B. \(\frac{1}{5}\) \(\begin{vmatrix} 4 & -3 \\ -1 & 2\end{vmatrix}\)
C. \(\frac{1}{5}\) \(\begin{vmatrix} 2 & -1 \\ -3 & 4\end{vmatrix}\)
D. \(\frac{1}{5}\) \(\begin{vmatrix} 4 & 3 \\ 1 & 2\end{vmatrix}\)

Question 4:

• JAMB 2013

Find the inverse \(\begin{pmatrix} 5 & 3 \\ 6 & 4 \end{pmatrix}\)

A. \(\begin{vmatrix} 2 & -\frac{3}{2} \\ -3 & -\frac{5}{2} \end{vmatrix}\)
B. \(\begin{vmatrix} 2 & -\frac{3}{2} \\ -3 & \frac{5}{2} \end{vmatrix}\)
C. \(\begin{vmatrix} 2 & \frac{3}{2} \\ -3 & \frac{5}{2} \end{vmatrix}\)
D. \(\begin{vmatrix} 2 & \frac{3}{2} \\ -3 & \frac{5}{2} \end{vmatrix}\)