2009 - WAEC Mathematics Past Questions & Answers - page 1

1
Simplify: (3\(\frac{1}{2} + 4\frac{1}{3}) \div (\frac{5}{6} - \frac{2}{3}\))
A
1\(\frac{1}{4}\)
B
8\(\frac{1}{2}\)
C
35
D
47
CORRECT OPTION: d
(3\(\frac{1}{2} + 4\frac{1}{3}) \div (\frac{5}{6} - \frac{2}{3}\)) = (7\(\frac{3 + 2}{6}) \div \frac{(5 - 4)}{6}\)

7\(\frac{5}{6} \div \frac{1}{6} = \frac{47}{6} \times \frac{6}{1}\) = 47
2
In a particular year, the exchange rate of naira (N) varies directly with the Dollars{$}. If N1122 is equivalent to $8, find the Naira equivalent of $36
A
N8976
B
N5049
C
N140.25
D
N31.17
CORRECT OPTION: b
N1122 = $8; x = $36

x x $8 = N1122 x $36

\(\frac{N1122 \times $36}{$8}\) = x

x = N5049
3
If log 2 = x, log 3 = y and log 7 = z, find, in terms of x, y and z, the value of log (\(\frac{28}{3}\))
A
2x + y - z
B
2x + x - y
C
x + y - 2x
D
x + x - y
CORRECT OPTION: b
log (\(\frac{28}{3}) = \log (\frac{7 \times 4}{3})\)

= log 7 + log 4 - log 3

log 7 + log 22 - log 3 = log 7 + 2 - log 3

= x + 2x - y

= 2x + x - y
4
Arrange the following numbers in descending orders of magnitude: 22three, 34five, 21six
A
21six, 22three, 34five,
B
21six, 34five, 22three
C
22three, 34five, 21six
D
34five, 21six, 22three
CORRECT OPTION: d
22three, 34five, 21six = (2 x 3)(2 x 3o), (3 x 51) = (4 x 50), (2 x 61) + (1 x 60)

= (6 + 2), (15 + 4), (12 + 1) = 8ten, 29ten, 13ten in descending order

29ten, 13ten, 8ten = 34five, 21six, 22three
5
Find the value to which N3000.00 will amount in 5 years at 6% per annum simple interest
A
N3,900.00
B
N3,750.00
C
N3,600.00
D
N3,300
CORRECT OPTION: a
A = P + I

p + \(\frac{PRT}{100}\)

A = N3000 (1 + \(\frac{6 \times 5}{100}\))

= N3000(1 + 0.3)

A = N3000 (1.3)

= N3,900.00
6
Express the square root of 0.000144 in the standard form
A
1.2 x 10-4
B
1.2 x 10-3
C
1.2 x 10-2
D
1.2 x 10-1
CORRECT OPTION: c
\(\sqrt{0.000144}\) = 0.012

= 1.2 x 10-2
7
Two sets are disjoint if
A
they are both empty
B
their union is an empty set
C
their intersection is an empty set
D
one of them is a subset of the other
CORRECT OPTION: c
8
If \(\frac{3}{2x} - \frac{2}{3x} = 4\), solve for x
A
\(\frac{4}{5}\)
B
\(\frac{4}{13}\)
C
\(\frac{5}{24}\)
D
\(\frac{13}{24}\)
CORRECT OPTION: c
\(\frac{3}{2x} - \frac{2}{3x} = 4\)

\(\frac{9 - 4}{6x}\); \(\frac{5}{6x}\) = 4

5 = 24x ; x = \(\frac{5}{24}\)
9
If (2x + 3)3 = 125, find the value of x
A
1
B
2
C
3
D
4
CORRECT OPTION: a
(2x + 3 )2 = 125

2n + 3 = 3\(\sqrt{125}\)

2x + 3 = 5

2x = 5 - 3

x = \(\frac{2}{2}\)

= 1
10
Factorize x2 - 2x - 3xy completely
A
(x - 2)(3x - y)
B
(x - 3y)(x - 2)
C
(x - 3y)(x - 3y)
D
(3x + y)(x - 2)
CORRECT OPTION: b
x2 - 2x - 3xy + 6y = x(x - 2) -3y(x - 2)

= (x - 3y)(x - 2)
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