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.

671.

Use the quadratic equation curve to answer this questions
What is the minimum value of the graph?

A.

-5.3

B.

0.5

C.

3

D.

8

Correct answer is A

The minimum value is the lowest value of the curve on y axis which gives a value of -5.3

672.

Find the equation of the tangent at the point (2, 0) to the curve y = x\(^2\) - 2x

A.

y = 2x - 4

B.

y = 2x + 4

C.

y = 2x - 2

D.

y = 2x + 2

Correct answer is A

The gradient to the curve is found by differentiating the curve equation with respect to x

  So \(\frac{dy}{dx}\) 2x - 2

  The gradient of the curve is the same with that of the tangent.

  At point (2, 0) \(\frac{dy}{dx}\) = 2(2) - 2

  = 4 – 2 = 2

  The equation of the tangent is given by (y - y1) \(\frac{dy}{dx}\) (x – x1)

  At point (x1, y1) = (2, 0)

  y - 0 = 2(x - 2)

  y = 2x - 4

673.

Evaluate (2√3 - 4) (2√3 + 4) 

A.

-4

B.

-2

C.

2

D.

4

Correct answer is A

2√3 - 4) ( 2√3 + 4) = 12 + 8√3 - 8√3 – 16 = 12 – 16 = -4 The two expressions in the bracket are conjugate of each other

674.

Express 495g as a percentage of 16.5kg

A.

3%

B.

3 \(\frac{1}{3}\)%

C.

15%

D.

30%

Correct answer is A

The two numbers must be expressed in the same unit. To convert 495g to kg, it will be divided by 1000

  495g = \(\frac{495}{1000}\)

  = 0.495kg

  To express in percentage, 0.495 will be divided by 16.5 and then multiplied by 100

  % will be added to the answer \(\frac{0.4950}{16.5}\) x 100

  = 3%

675.

In the figure below, /MX/ = 8cm, /XN/ = 12cm, /NZ/ = 4cm and ∠ XMN = ∠ XZY. Calculate /YM/

A.

32cm

B.

24 cm

C.

16 cm

D.

12 cm

Correct answer is C

From the figure,

  ∠ XMN = ∠ XZY

  Angle X is common

  So, ∠ XNM = ∠ XYZ

  Then from the angle relationship

  \(\frac{XM}{XZ}\) = \(\frac{XN}{XY}\) = \(\frac{MN}{ZY}\)

  XM = 8, XZ = 12 + 4 = 16,

  XN = 12, XY = 8 + YM

  \(\frac{8}{16}\) = \(\frac{12}{(8 + YM) }\)

  Cross multiply

  8(8 + YM) = 192

  64 + 8YM = 192

  8YM = 128

  YM = \(\frac{128}{8}\)

  = 16cm