1989 - WAEC Mathematics Past Questions and Answers - page 3

21
Calculate the surface area of a hallow cylinder which is closed at one end, if the base radius is 3.5cm and the height 8cm.[take π = 22/7]
A
126.5cm2
B
165cm2
C
176cm2
D
214.5cm2
correct option: d
since it is an open cylinder; r= 3.5cm = 7/2cm
h= 8cm;
S.A = 2πrh + πr 2

= πr(2h + r)
(16 + 3.5); 11 x 19.5 = 214.5cm2
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22

Solve the following equation: 6x\(^2\) - 7x - 5 = 0

A
x = 1/2 or x = -21/2
B
x = 1/3 or x = 21/2
C
x = 1 2/3 or x = -1/2
D
x = 12/3 or x = 1/2
correct option: c

6x\(^2\) - 7x - 5 = 0

6x\(^2\) - 10x + 3x - 5 = 0

2x(3x - 5) + 1(3x - 5) = 0

(2x + 1)(3x - 5) = 0

x = \(\frac{5}{3}\) or x = \(-\frac{1}{2}\)

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23

What angle represents grown up girls ? Correct to one decimal place

A
37.5o
B
26.7o
C
25.7o
D
20o
correct option: b

Total population = 1400 + 550 + 200 + 150 + 400 = 2700

grown up girls = 200

= \(\frac {200}{2700}\) x \(\frac {360}{1}\)

=80/3 = 26.7°

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24
What percentage of the population are married? correct to one decimal place
A
14.8%
B
20.4%
C
30.5%
D
35.2%
correct option: d
Married = 550 + 400 = 950

Married% = \(\frac {950}{2700}\) x \(\frac {100}{1}\)

=35.2%
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25

If A = {a,b,c}, B = {a,b,c,d,e} and C = {a,b,c,d,e,f}. Find (A∪B)∩(A∪C)

A
{a,b,c,d}
B
{a,b,c,d,e}
C
{a,b,c,d,e,f}
D
{a,b,c}
correct option: b

A = {a, b, c};  B = {a, b, c, d, e}; C = {a, b, c, d, e, f}

(A \(\cup\) B) = {a, b, c, d, e}

(A \(\cup\) C) = {a, b, c, d, e, f}

(A \(\cup\) B) \(\cap\) (A \(\cup\) C) = {a, b, c, d, e}

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26

For a class of 30 students, the scores in a Mathematics test out of 10 marks were as follows;


4,5,7,2,3,6,5,5,8,9,5,4,2,3,7,9,8,7,7,7,3,4,5,5,2,3,6,7,7,2

What is the mode of the score
A
3
B
4
C
5
D
6
correct option: e
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27

For a class of 30 students, the scores in a Mathematics test out of 10 marks were as follows;


4,5,7,2,3,6,5,5,8,9,5,4,2,3,7,9,8,7,7,7,3,4,5,5,2,3,6,7,7,2

What is the median score?
A
2
B
7
C
8
D
9
correct option: c
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28

For a class of 30 students, the scores in a Mathematics test out of 10 marks were as follows;


4,5,7,2,3,6,5,5,8,9,5,4,2,3,7,9,8,7,7,7,3,4,5,5,2,3,6,7,7,2

What is the range of the distribution?
A
2
B
7
C
8
D
9
correct option: b
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29

In the diagram above O is the center of the circle, if ∠PAQ = 75o, what is the value of ∠PBQ?

A
15o
B
75o
C
105o
D
150o
correct option: c

< PBQ = 180° - 75° (opp angles of a cyclic quadrilateral)

= 105°

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30

Simplify \(\frac{9^{-\frac{1}{2}}}{27^{\frac{2}{3}}}\)

A
1
B
1/3
C
1/9
D
1/18
correct option: e

\(\frac{9^{-\frac{1}{2}}}{27^{\frac{2}{3}}}\)

=\(\frac{3^{-1}}{3^2}\) = \(\frac{1}{27}\)

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