2012 - WAEC Mathematics Past Questions and Answers - page 4
31
Factorise completely: 32x2y - 48x3y3
A
16x2y(2 - 3xy2)
B
8xy(4x - 6x2y2)
C
8x2y(4 - 6xy2)
D
16xy(2x - 3x2y2)
correct option: a
Users' Answers & Comments32
If x and y are variables and k is a constant, which of the following describes an inverse relationship between x and y?
A
y = kx
B
y = \(\frac{k}{x}\)
C
y = k\(\sqrt{x}\)
D
y = x + k
correct option: b
Users' Answers & Comments33
If x and y are variables and k is a constant, which of the following describes an inverse relationship between x and y?
A
y = kx
B
y = \(\frac{k}{x}\)
C
y = k\(\sqrt{x}\)
D
y = x + k
correct option: b
Users' Answers & Comments34
In the diagram, |QR| = 10m, |SR| = 8m
< QPS = 30o, < QRP = 90o and |PS| = x, Find x
< QPS = 30o, < QRP = 90o and |PS| = x, Find x
A
1.32m
B
6.32m
C
9.32m
D
17.32
correct option: c
In right angled \(\bigtriangleup\)QPR
tan 30o = \(\frac{10}{x + 8}\)
(x + 8) tan 30 = 10
x + 8 = \(\frac{10}{0.5773}\)
x +8 = 17.3
x = 17.3 - 8
x = 9.32
Users' Answers & Commentstan 30o = \(\frac{10}{x + 8}\)
(x + 8) tan 30 = 10
x + 8 = \(\frac{10}{0.5773}\)
x +8 = 17.3
x = 17.3 - 8
x = 9.32
35
In the diagram, O is a circle centre of the circle PQRS and < PSR = 86o. If < PQR = xo, find x
A
108o
B
172o
C
130o
D
50o
correct option: b
xo = 86 x 2(angle at centre = 2 x angle at circumference)
= 172o
Users' Answers & Comments= 172o
36
The diagram is a circle centre O. If < SPR = 2m and < SQR = n, express m in terms of n
A
m = \(\frac{n}{2}\)
B
m = 2n
C
m = n - 2
D
m = n + 2
correct option: a
If < SPR = 2m then < SQR = 2m but < AQR was n
n = 2m
m = \(\frac{n}{2}\)
Users' Answers & Commentsn = 2m
m = \(\frac{n}{2}\)
37
In the diagram, MQ//RS, < TUV = 70o and < RLV = 30o. Find the value of x
A
150o
B
110o
C
100o
D
95o
correct option: c
L + 30o - 180o(Sum of < s on straight line)
L = 180o - 30o = 150o
L = q = 150o(opposite < s are equal)
y = b = 30o(alt. < s)
b + c = 180o(sum of < s on str. line)
30o + c 180
c = 180 - 30
c = 150o
b = a = 30o (opp < s are equal)
c = d = 150o (opp < s are equal)
a + k + 70o = 180o (sum of < s on \(\bigtriangleup\))
30o + k + 70o = 180
k + 100o = 180
k = 180 - 100
k = 80o
x + 80o = 180(sum of < s on straight line)
x = 180o - 80o
x = 100o
Users' Answers & CommentsL = 180o - 30o = 150o
L = q = 150o(opposite < s are equal)
y = b = 30o(alt. < s)
b + c = 180o(sum of < s on str. line)
30o + c 180
c = 180 - 30
c = 150o
b = a = 30o (opp < s are equal)
c = d = 150o (opp < s are equal)
a + k + 70o = 180o (sum of < s on \(\bigtriangleup\))
30o + k + 70o = 180
k + 100o = 180
k = 180 - 100
k = 80o
x + 80o = 180(sum of < s on straight line)
x = 180o - 80o
x = 100o
38
Is the diagram, MN, PQ and RS are three intersecting straight lines. Which of the following statements is/are true? i. t = y ii. x + y + z + m = 180o ii. x + m + n = 180o iv. x + n = m + z
A
i and iv
B
ii
C
iii
D
iv
correct option: c
m + y + x = 180o(sum of < s on straight line)
y = n(vertically opp. angle)
m + n + x = 180o
Users' Answers & Commentsy = n(vertically opp. angle)
m + n + x = 180o
39
The position of three ships P,Q and R at sea are illustrated in the diagram. The arrows indicated the North direction. The bearing of Q from P is 050o and < PQR = 72o. Calculate the bearing of R and Q
A
155o
B
80o
C
158o
D
91o
correct option: c
< NPQ = < PQB = 50o(alt. < s)
< PQB = 50o
< PQR = < PQR < PQB + < QBR = 72o
< QBR = < PQR - < PQB = 72o - 50o
= 22o
< NQR = 180 - < QBR = 180o - 22 = 158o, the bearing of R from Q = 158o
Users' Answers & Comments< PQB = 50o
< PQR = < PQR < PQB + < QBR = 72o
< QBR = < PQR - < PQB = 72o - 50o
= 22o
< NQR = 180 - < QBR = 180o - 22 = 158o, the bearing of R from Q = 158o
40
The bar chart shows the frequency distribution of marks scored by students in a class test. How many students are in the class?
A
10
B
24
C
25
D
30