2015 - WAEC Mathematics Past Questions and Answers - page 3

21
PQRT is square. If x is the midpoint of PQ, Calculate correct to the nearest degree, LPXS
A
53o
B
55o
C
63o
D
65o
correct option: c
In the diagram given,

tan\(\alpha\) = \(\frac{1}{0.5}\) = 2

\(\alpha\) = tan - 1(2) = 63.43o

= 63o
Users' Answers & Comments
22
The angle of elevation of an aircraft from a point K on the horizontal ground 30\(\alpha\). If the aircraft is 800m above the ground, how far is it from K?
A
400.00m
B
692.82m
C
923.76m
D
1,600.99m
correct option: d
In \(\bigtriangleup\)KBC, sin 30 = \(\frac{800}{IKCI}\)

IKCL = \(\frac{800}{sin30^o}\)

= \(\frac{800}{0.5}\)

= 1600m
Users' Answers & Comments
23
The population of students in a school is 810. If this is represented on a pie chart, calculate the sectoral angle for a class of 7 students
A
32o
B
45o
C
60o
D
75o
correct option: a
In a school with students' population 810, the sectoral angle for a class of 7 students is

= \(\frac{72}{810}\) x 360o

= 32o
Users' Answers & Comments
24
The scores of twenty students in a test are as follows: 44, 47, 48, 49, 50, 51, 52, 53, 53, 54, 58, 59, 60, 61, 63, 65, 67, 70, 73, 75. Find the third quartile.
A
62
B
63
C
64
D
65
correct option: b
Third quartile Q3 = \(\frac{3}{4}\)Nth

= \(\frac{3}{4}\) x 20th score

= 15th score

= 63
Users' Answers & Comments
25
\(\begin{array}{c|c}
Scores & 0 - 4 & 5 - 9 & 10 - 14\
\hline Frequency & 2 & 1 & 2\end{array}\)

The table shows the distribution of the scores of some students in a test. Calculate the mean scores.
A
5.6
B
6.2
C
6.6
D
7.0
correct option: d
Users' Answers & Comments
26
The probability that kebba, Ebou and Omar will hit a target are \(\frac{2}{3}\), \(\frac{3}{4}\) and \(\frac{4}{5}\) respectively. Find the probability that only Kebba will hit the target.
A
\(\frac{2}{5}\)
B
\(\frac{7}{60}\)
C
\(\frac{1}{30}\)
D
\(\frac{1}{60}\)
correct option: c
Hence the probability that only Kebba will hit the target

= P(K)xP(E')xP(O')

= \(\frac{2}{3} \times \frac{1}{4} \times \frac{1}{5}\)

= \(\frac{1}{30}\)
Users' Answers & Comments
27
In the diagram, VW//YZ, |WX| = 6cm, |XY| = 16cm, |YZ| = 20cm and |ZX| = 12cm. Calculate |VX|
A
3cm
B
4cm
C
6cm
D
8cm
correct option: d
In the diagram, \(\frac{16}{12} = \frac{VX}{6}\) (similar \(\Delta\)s)

VX = \(\frac{16 \times 6}{12}\)

= 8cm
Users' Answers & Comments
28
Tom will be 25 years old in n years' time. If he is 5 years younger than Bade's present age.
A
(30 - n)years
B
(20 - n)years
C
(25 - n)years
D
(30 + n)years
correct option: a
Let Tom's present agr be x.

Then x = 25 - n

If Tom is 5 years younger than Bade, then Bade's present age is x + 5 = 25 - n + 5

= (30 - n)
Users' Answers & Comments
29

If \(\frac{\sqrt{2} + \sqrt{3}}{\sqrt{3}}\) is simplified as m + n\(\sqrt{6}\), find the value of (m + n)

A
\(\frac{1}{3}\)
B
\(\frac{2}{3}\)
C
1\(\frac{1}{3}\)
D
1\(\frac{2}{3}\)
correct option: c

\(\frac{\sqrt{2} + \sqrt{3}}{\sqrt{3}}\) = \(\frac{\sqrt{2} + \sqrt{3}}{\sqrt{3}}\) x \(\frac{\sqrt{3}}{\sqrt{3}}\)

= \(\frac{\sqrt{2} \times \sqrt{3} + \sqrt{3} \times \sqrt{3}}{\sqrt{3} \times \sqrt{3}}\)

= \(\frac{\sqrt{6} + 3}{3}\)

= \(\frac{3 + \sqrt{6}}{3}\)

= Hence, (m + n) = 1 + \(\frac{1}{3}\)


= 1\(\frac{1}{3}\)

Users' Answers & Comments
30

In the given diagram, \(\bar{QT}\) and \(\bar{PR}\) are straight lines, < ROS = (3n - 20), < SOT = n, < POL = m and < QOL is a right angle. Find the value of n.

A
35o
B
40o
C
55o
D
60o
correct option: a

In the diagram, QOR + 2m(vertically opposite angles)

So, m + 90° + 2m = 180°

(angles on str. line)

3m = 180° - 90°

3m = 90°

m = \(\frac{90^o}{3}\)

= 30°

substituting 30° for m in

2m + 4n = 200° gives

2 x 30° + 4n = 200°

60° + 4n = 200°

4n = 200° - 60°

= 140°

n = \(\frac{140°}{4}\)

= 35°

Users' Answers & Comments
Please share this, thanks: