Jamb Mathematics 1994 Past Questions and Answers

Question 21:

• JAMB 1994

A binary operation \(\oplus\) is defines on the set of all positive integers by a \(\oplus\) b = ab for all positive integers a, b. Which of the following properties does NOT hold?

A. Closure
B. Identity
C. Positive
D. Inverse

Question 22:

• JAMB 1994

\(\begin{array}{c|c} \oplus mod 10 & 2 & 4 & 6 & 8 \\ \hline 2 & 4 & 8 & 2 & 6 \\4 & 8 & 6 & 4 & 2\\ 4 & 8 & 6 & 4 & 2\\ 6 & 2 & 4 & 6 & 8\\ 8 & 6 & 2 & 8 & 4\end{array}\)
The multiplication table above has modulo 10 on the set S = (2, 4, 6, 8). Find the inverse of 2

A. 2
B. 4
C. 6
D. 8

Question 23:

• JAMB 1994

Solve for x and y \(\begin{pmatrix} 1 & 1 \\ 3 & y \end{pmatrix}\)\(\begin{pmatrix} x \\ 1 \end{pmatrix}\) = \(\begin{pmatrix} 4 \\ 1\end{pmatrix}\)

A. X = 3, y = 8
B. X = 3, y = -8
C. X = -8, y = 3
D. X = 8, y = -3

Question 24:

• JAMB 1994

The determination of the matrix \(\begin{pmatrix} 1 & 3 & 3 \\ 4 & 5 & 6\\ 2 & 0 & 1 \end{pmatrix}\) is

A. -67
B. -57
C. -3
D. 3

Question 25:

• JAMB 1994

\(\begin{array}{c|c} \text{Age in years} & 10 & 11 & 12 \\ \hline \text{Number of pupils} & 6 & 27 & 7\end{array}\)
The table above shows the number of pupils in each age group in a class. What is the probability that a pupil chosen at random is at least 11 years old?

A. \(\frac{27}{40}\)
B. \(\frac{17}{20}\)
C. \(\frac{33}{40}\)
D. \(\frac{3}{20}\)