Mathematics questions and answers

Mathematics Questions and Answers

How good are you with figures and formulas? Find out with these Mathematics past questions and answers. This Test is useful for both job aptitude test candidates and students preparing for JAMB, WAEC, NECO or Post UTME.

3,621.

A regular polygon has 150º as the size of each interior angle. How many sides does it have?

A.

12

B.

10

C.

9

D.

8

Correct answer is A

Sum of interior angles of a polygon = each interior ∠ x n
(n-2)180 = 150 x n
180n - 360 = 150n
180n-150n = 360
30n = 360
n = 360/30
n = 12 sides

3,622.

Find the acute angle between the straight lines y = x and y = √3x

A.

15o

B.

30o

C.

45o

D.

60o

Correct answer is A

y = x, Gradient (m1) = 1
y = √3x gradient (m2) = √3
\(tan\theta = \frac{m_2 - m_1}{1+m_2 m_1}\\
tan\theta = \frac{\sqrt{3}-1}{1+\sqrt{3}\times 1}\\
=\frac{1.73 -1 }{1+1.73}=
\frac{0.73}{2.73}=0.268\)
θ = Tan-1 (0.268)
= 15o

3,623.

If P \(=\left[\begin{array}{cc}x+3 & x+2\\
x+1 & x-1\end{array}\right]\) evaluate x if |P| = -10

A.

-5

B.

-2

C.

2

D.

5

Correct answer is D

\(P=\left[\begin{array}{cc}x+3 & x+2\\
x+1 & x-1\end{array}\right]\) evaluate x if |P| = -10
(x+3)(x-1) - {(x+1)(x+2)} = -10
x2 - x + 3x - 3 - {x2 + 2x + x + 2} = -10
x2 + 2x - 3 - {x2 + 3x + 2} = -10
-x - 5 = -10
-5 + 10 = x
5 = x
∴x = 5

3,624.

If Q is\( \left[ \begin{array}{cc}
9 & -2 \\
-7 & 4 \\
\end{array} \right]\) , then |Q| is?

A.

-50

B.

-22

C.

22

D.

50

Correct answer is C

Q = \( \left[ \begin{array}{ccc}
9 & -2 \\
-7 & 4 \\
\end{array} \right]\)
|Q| = 9x4 - (-2x7)
= 36 - 14
= 22

3,625.

A binary operation ⊗ defined on the set of integers is such that m⊗n = m + n + mn for all integers m and n. Find the inverse of -5 under this operation, if the identity element is 0?

A.

-5/4

B.

-5/6

C.

zero

D.

5

Correct answer is A

\(m \otimes n = m + n + mn\)

Let the inverse of -5 be n.

\(\therefore -5 \otimes n = 0\)

\(-5 + n + (-5n) = 0\)

\(n - 5n = 5 \implies -4n = 5\)

\(n = -\frac{5}{4}\)