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.

3,726.

If \(T = 2\pi \sqrt{\frac{l}{g}}\), make g the subject of the formula

A.

(4π l2) / T

B.

(4π2l) / T2

C.

(4π2l2) / T2

D.

(2π√l) / T

Correct answer is B

\(T = 2\pi \sqrt{\frac{l}{g}}\)

\(\frac{T}{2\pi} = \sqrt{\frac{l}{g}}\)

\((\frac{T}{2\pi})^{2} = \frac{l}{g}\)

\(\therefore g = \frac{4 \pi^{2} l}{T^{2}}\)

3,727.

The sum of the first n positive integers is

A.

1/2 n(n-1)

B.

n(n+1)

C.

n(n-1)

D.

1/2 n(n+1)

Correct answer is D

Let the positive integers be 1, 2, ,3, 4, .....n
∴ a = 1, d = 1 and n = n
Sn = n/2(2a + (n-1)d)
= n/2 (2 + n – 1)
= 1/2n(n + 1)

3,728.

The cost of renovating a 6 m square room is N540. What is the cost of renovating a 9 m square room?

A.

N1215

B.

N720

C.

N1620

D.

N810

Correct answer is D

Cost of removing a 6m\(^2\) room = N540
Cost of renovating a 1m\(^2\) room = 540 / 6
Cost of removing a 9m\(^2\) room
= (540 / 6) * 9
= N810

3,729.

Solve the inequalities for which \(\frac{x+4}{3}-\frac{x-3}{2} < 4\)

A.

x < 7

B.

x > -7

C.

x < -7

D.

x > 7

Correct answer is B

\(\frac{x+4}{3}-\frac{x-3}{2} < 4\\
\frac{(2(x+4))-(3(x-3))}{6}<4\)
2(x+4) – 3(x-3) < 4 x 6
2x + 8 – 3x+9 < 24
-x + 17 < 24
-x < 24 – 17
-x < 7
x > -7

3,730.

Find the value of k if the expression kx3 + x2 - 5x - 2 leaves a remainder 2 when it is divided by 2x + 1

A.

10

B.

8

C.

-10

D.

-8

Correct answer is C

F(x) = Q x D + R
Kx3 + x2 - 5x – 2 = Q(2x+1)+R
If 2x+1 = 0 implies x = -1/2
∴k(-1/2)3 + (-1/2)2 -5(-1/2) -2
= Q(2(-1/2) + 1) +2
K(-1/8) + 1/4 + 5/2 - 2 = Q(-1+1)+2
-k/8 + 1/4 + 5/2 - 2 = 0+2
(-k+2+20-16) / 8 = 2
(-k+6) / 8 = 2
-k+6 = 2*8
-k+6 = 16
-k = 16-6
-k = 10
∴k = -10