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WAEC Further Mathematics Past Questions & Answers - Page 142

706.

A straight line 2x+3y=6, passes through the point (-1,2). Find the equation of the line.

A.

2x-3y=2

B.

2x-3y=-2

C.

2x+3y=-4

D.

2x+3y=4

Correct answer is D

2x+3y=63y=62x

y=632x3 

Parallel lines have the same gradient

Gradient of the line = \frac{-2}{3}

Line passes through (-1,2)

Equation: \frac{y-2}{x-(-1)} = \frac{y-2}{x+1} = \frac{-2}{3}

3y-6 = -2x-2 \implies 3y+2x = -2+6 =4

707.

Express cos150° in surd form.

A.

-\sqrt{3}

B.

-\frac{\sqrt{3}}{2}

C.

-\frac{1}{2}

D.

\frac{\sqrt{2}}{2}

Correct answer is B

cos150° = -cos30°

 = -\frac{\sqrt{3}}{2}

708.

If \begin{pmatrix}  2  &  1 \\  4 & 3 \end{pmatrix}\begin{pmatrix}  5 \\ 4 \end{pmatrix}  = k\begin{pmatrix}  17.5 \\ 40.0 \end{pmatrix}, find the value of k.

A.

1.2

B.

3.6

C.

0.8

D.

0.5

Correct answer is C

\begin{pmatrix}  2  &  1 \\  4 & 3 \end{pmatrix}\begin{pmatrix}  5 \\ 4 \end{pmatrix}  = k\begin{pmatrix}  17.5 \\ 40.0 \end{pmatrix}

\begin{pmatrix}  10 + 4  \\  20 + 12\end{pmatrix} = \begin{pmatrix}  14 \\ 32\end{pmatrix} = k\begin{pmatrix}  17.5 \\ 40.0 \end{pmatrix}

k = \frac{14}{17.5} = \frac{32}{40} = 0.8

709.

How many ways can 6 students be seated around a circular table?

A.

36

B.

48

C.

120

D.

720

Correct answer is C

In a circular seating arrangement, we fix the position of one person and then rotate the others, so we have

(6-1)! = 5! = 5\times4\times3\times2 = 120

710.

Find the 21st term of the Arithmetic Progression (A.P.):  -4, -1.5, 1, 3.5,...

A.

43.5

B.

46

C.

48.5

D.

51

Correct answer is B

T_{n} = a + (n-1)d

d = T_{2} - T_{1} = T_{3} - T_{2} = -1.5 - (-4) = 2.5

T_{21} = -4 + (21 - 1) \times 2.5 = -4 + (20\times 2.5)

= -4 + 50 = 46