2004 - WAEC Mathematics Past Questions and Answers - page 2

11
Find the area of a rectangle of length 4cm and whose diagonal is 6cm, (Leave your answer in surd form)
A
8√3cm2
B
12√3cm2
C
16√2cm2
D
16√3cm2
correct option: d
|AB| = 4cm
|BC| = 8cm
In right-angled BAC; |BC|22
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12
Given that x + y = 7 and 3x-y = 5, evaluate \(\frac{y}{2}-3\).
A
-1
B
1
C
3
D
4
correct option: a
\(x + y = 7 ------ I\
3x – y = 5 ------ II\)
Add I and II;
\(4x = 12 => x = \frac{12}{4} = 3\
Y = 7 – 3 = 4, evaluate \hspace{1mm} \frac{y}{2} – 3\
\frac{4}{2} – 3 => 2-3 = -1\)
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13

In the diagram, POQ is the diameter of the circle centre O. Calculate ∠QRS

A
35o
B
70o
C
100o
D
125o
correct option: a

∠PSQ = 90° (angle in a semi-circle)
(when SR is joined to SP)
∠SPQ = 180 – (90+35) = 180 – 125 = 55°
∠QRS + ∠SPQ = 180° (opposite angles in a cyclic quad is supplementary)
∠QRS = 180° - 55°
= 125°

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14

If \(\left(\frac{1}{4}\right)^{(2-y)} = 1\), find y.

A
-2
B
\(-\frac{1}{2}\).
C
\(\frac{1}{2}\)
D
2
correct option: d

\(2^{-2(2-y)}-x=2^{0}; -4 + 2y = 0\
2y = 4; y = 2\)

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15
Calculate the total surface area of a cupboard which measures 12cm by 10cm by 8cm
A
1920cm2
B
592cm2
C
296cm2
D
148cm2
correct option: c
Total surfaced area of a cupboard = lb + lh + bh
l = length h = height b = base
l = 12cm h = 10cm b = 8cm
T.S.A \(= (12 \times 8 \times 12 \times 10 + 8 \times 10)cm^\
= (96 + 120 + 80)cm^2 = 296cm^2\)
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16
If \(\frac{x}{a+1}+\frac{y}{b}\) 1. Make y the subject of the relation
A
\(\frac{b(a-x+1)}{a+1}\)
B
\(\frac{a+1}{b(a-x+1)}\)
C
\(\frac{a(b-x+1)}{b+1}\)
D
\(\frac{b}{a(b-x+1)}\)
correct option: a
If \(\frac{bx+y(a+1)}{b(a+1)}=1\
bx + ya + y = ba + b; y(a+1) = ba+b-bx\
y(a+1)=b(a+1-x); y = \frac{b(1+a-x}{a+1}\)
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17

lf \(log_q p= r\), express p in terms of q and r

A
p =qr
B
p =rq
C
\(p = \frac{r}{q}\)
D
p=qr
correct option: d

If \(log_q p\) = r convert from logarithm to indices
P = q\(^r\)

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18

Find the next two terms of the sequence
1, 5, 14, 30, 55, ...

A
61,110
B
67,116
C
81,140
D
91, 140
correct option: d

\(1 + 2^2 = 5 + 3^2 = 14 + 4^2 = 30 + 5^2 = 55\)

\(55 + 6^2 = 91 + 7^2 = 140\).

91, 140 are the next two terms.

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19

Each interior angle of a regular polygon is 108°. How many sides has it?

A
5
B
7
C
9
D
14
correct option: a

The exterior angle of the polygon = 180 – 108 = 72°. The sum of exterior angle of the regular polygon = 360°
The number of sides \(=\frac{360}{72}=5\)

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20
Solve the equation 10-3x-x2 = 0
A
x=2 or-5
B
x= -2 or 5
C
x = 1 or 10
D
x = 2 or 5
correct option: a
10 – 3x - x2 = 0; 10 – 5x + 2x - x2 = 0
5(2 – x) + x(2 – x) = 0; (2 – x)(5 + x) = 0
2 – x = 0 or 5 + x = 0; x = 2 or x = -5
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