WAEC Further Mathematics Past Questions & Answers - Page 52

256.

Marks 5 - 7 8 - 10 11 - 13 14 -  16 17 - 19 20 - 22
Frequency 4 7 26 41 14 8

The table above shows the marks obtained by 100 pupils in a test. Find the probability that a student picked at random scored at least 14 marks.

A.

0.22

B.

0.41

C.

0.49

D.

0.63

Correct answer is D

No explanation has been provided for this answer.

257.

Marks 5 - 7 8 - 10 11 - 13 14 -  16 17 - 19 20 - 22
Frequency 4 7 26 41 14 8

The table above shows the marks obtained by 100 pupils in a test. Find the upper class boundary of the class containing the third quartile.

A.

13.0

B.

16.0

C.

16.5

D.

22.5

Correct answer is C

The third quartile can be found in the \((\frac{3N}{4})^{th}\) position

= \((\frac{3 \times 100}{4})^{th}\) position

This is found in the class 14 - 16.

The upper class boundary = 16.5

258.

The polynomial \(2x^{3} + 3x^{2} + qx - 1\) has the same reminder when divided by \((x + 2)\) and \((x - 1)\). Find the value of the constant q.

A.

-11

B.

-9

C.

-3

D.

4

Correct answer is C

Using the remainder theorem, the remainder when a polynomial \(ax^{2} + bx + c\) is divided by \((x - a)\) is equal to \(f(a)\).

\(2x^{3} + 3x^{2} + qx - 1\) divided by \((x + 2)\), the remainder = \(f(-2)\)

\(\implies f(-2) = f(1)\)

\(f(-2) = 2(-2^{3}) + 3(-2^{2}) + q(-2) - 1 = -16 + 12 - 2q - 1 = -5 - 2q\)

\(f(1) = 2(1^{3}) + 3(1^{2}) + q(1) - 1 = 2 + 3 + q - 1 = 4 + q\)

\(4 + q = -5 -2q \implies 4 + 5 = -2q - q = -3q\)

\(q = -3\)

259.

Find the value of p for which \(x^{2} - x + p\) becomes a perfect square. 

A.

\(-\frac{1}{2}\)

B.

\(\frac{1}{4}\)

C.

\(\frac{1}{2}\)

D.

\(1\)

Correct answer is B

The equation \(ax^{2} + bx + c\) is a perfect square if \(b^{2} = 4ac\).

\(x^{2} - x + p\)

\((-1)^{2} = 4(1)(p)\)

\(1 = 4p \implies p = \frac{1}{4}\)

260.

The equation of a curve is given by \(y = 2x^{2} - 5x + k\). If the curve has two intercepts on the x- axis, find the value(s) of constant k.

A.

\(k = \frac{8}{25}\)

B.

\(k = \frac{25}{8}\)

C.

\(k < \frac{25}{8}\)

D.

\(k > \frac{25}{8}\)

Correct answer is C

No explanation has been provided for this answer.