# 2009 - WAEC Mathematics Past Questions and 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)