Binary Operations - Jamb Mathematics Past Questions and Answers

Question 11:

• JAMB 1992

If the binary operation \(\ast\) is defined by m \(\ast\) n = mn + m + n for any real number m and n, find the identity of the elements under this operation

A. E = 1
B. E = -1
C. E = -2
D. E = 0

Question 12:

• JAMB 1993

A binary operation \(\ast\) is defined on a set of real numbers by x \(\ast\) y = x^y for all real values of x and y. If x \(\ast\) 2 = x. Find the possible values of x

A. 0, 1
B. 1, 2
C. 2, 2
D. 0, 2

Question 13:

• 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 14:

• 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 15:

• JAMB 1995

Which of the following binary operations is cumulative on the set of integers?

A. A \(\ast\) b = a + 2b
B. A \(\ast\) b = a + b - ab
C. A \(\ast\) b = a² + b
D. A \(\ast\) b = \(\frac{a(b + 1)}{2}\)