Year : 
2004
Title : 
Mathematics (Core)
Exam : 
WASSCE/WAEC MAY/JUNE

Paper 1 | Objectives

31 - 40 of 50 Questions

# Question Ans
31.

Find the average of the first four prime numbers greater than10

A. 20

B. 19

C. 17

D. 15

Detailed Solution

First four prime numbers greater than 10 are 11, 13, 17, 19
The average \(= \frac{11+13+17+19}{4}=15\)
32.

Given that \(\sqrt{128}+\sqrt{18}-\sqrt{K} = 7\sqrt{2}\), find K,

A. 8

B. 16

C. 32

D. 48

Detailed Solution

\(\sqrt{128} +\sqrt{18}-\sqrt{k}=7\sqrt{2}\\
\sqrt{2\times 64}+\sqrt{9\times 2} - \sqrt{k} = 7\sqrt{2}\\
8\sqrt{2} + 3\sqrt{2} - \sqrt{k} = 7\sqrt{2}; 11\sqrt{2} - \sqrt{k} = 7\sqrt{2}\\
-\sqrt{k}=7\sqrt{2}-11\sqrt{2}; -\sqrt{k} = -4\sqrt{2}; \sqrt{k}=4\sqrt{2}\\
=\sqrt{4^2\times 2} = \sqrt{16\times 2}; \sqrt{k}=\sqrt{32}; k = 32\)
33.

In the diagram, PQRW is a circle. Line P, V and QR are produced to meet at M, where ∠WMR = 30o and |WM| = |MR| Find the value of x

A. 10o

B. 25o

C. 35o

D. 60o

Detailed Solution

MPQ = PQM = 3x; ∆MPQ
MPQ + PQM + PMQ = 180o; 3x + 3x + 30o = 180o
6x \times 30o = 180o; 6x + 180o - 30o; 6x + 150o
\(x = \frac{150}{6} = 25^{\circ}\)
34.

The table above gives the marks scored by a group of students in a test Use the table to answer the Question below
What is the median mark?

A. 1

B. 2

C. 3

D. 4

Detailed Solution

Median = 0, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5
Median mark = \(\frac{3+3}{2} = \frac{6}{2} = 3\)
35.

The table above gives the marks scored by a group of students in a test Use the table to answer the Question below
What is the probability of selecting a student from the group that scored 2 or 3?

A. \(\frac{1}{11}\)

B. \(\frac{5}{22}\)

C. \(\frac{7}{22}\)

D. \(\frac{6}{11}\)

Detailed Solution

Prob (2 or 3) = prob(2) + prob(3)
Prob (mark 2) \(=\frac{7}{22}\) + Prob(mark 3) = \(\frac{5}{22}\)
Prob(2 or 3) \(=\frac{7}{22}+\frac{5}{22}=\frac{12}{22}=\frac{6}{11}\)
36.

Find the range of values of x for which\(\frac{x+2}{4}-\frac{x+1}{3}>\frac{1}{2}\)

A. x > 4

B. x > -4

C. x < 4

D. x < -4

Detailed Solution

\(\frac{x+2}{4}-\frac{x+1}{3}>\frac{1}{2}\\
\frac{3(x+2)-4(x+1)>6}{12}; 3x + 6 – 4x – 4 > 6\
-x +2>6; -x > 4; x < -4\)
37.

A boy walks 800m in 20 minutes. Calculate his average speed in km per hour

A. 2.4

B. 4

C. 16

D. 24

Detailed Solution

\(Average \hspace{1mm}speed = \frac{Distance}{Time\hspace{1mm} taken}\\
Distance = 800m = \frac{800}{1000}km = 0.8km\\
Time\hspace{1mm}taken = 20\hspace{1mm}minutes = \frac{20}{60}hr=\frac{1}{3}hr\\Average \hspace{1mm} speed = \left(0.8\div \frac{1}{3}\right)km/hr = (0.8\times3)km/hr\\=2.4km/hr\)
38.

Simplify \(\frac{2}{a+b}-\frac{1}{a-b}\)

A. \(\frac{3}{a+b}\)

B. \(\frac{a-3b}{a^2-b^2}\)

C. \(\frac{3a-b}{a^2 – b^2}\)

D. \(\frac{a-3b}{a^2+b^2}\)

Detailed Solution

Simplify \(\frac{2}{a+b}-\frac{1}{a-b}; \frac{2(a-b)-1(a+b)}{(a+b)(a-b)}\)

= \(\frac{2a-2b-a-b}{(a+b)(a-b)}\)

= \(\frac{a-3b}{a^2 - ab + ab - b^2}\)

= \(\frac{a-3b}{a^2-b^2}\)
39.

The diagram is a circle centre O. Find the value of x

A. 30o

B. 50o

C. 61o

D. 78o

E. 65.5\(^{\circ}\)

Detailed Solution

∠PQR (Reflex) = 360° – 68° = 292°
∠PQR = 2∠PQR
292° = 4x + 30°
4x = 292 – 30 = 262
\(x = \frac{262}{4}=65.5°\)
40.

Use the graph to answer the Question below
What are the roots of the equation x2 + 3x - 4 = 0?

A. 1, 4

B. -1, -4

C. -1, 4

D. -4, 1

Detailed Solution

x2 + 3x – 4 = 0 has roots value at the curve makes touches with the x – axis. The curve contact is at x = -4 and +1.
31.

Find the average of the first four prime numbers greater than10

A. 20

B. 19

C. 17

D. 15

Detailed Solution

First four prime numbers greater than 10 are 11, 13, 17, 19
The average \(= \frac{11+13+17+19}{4}=15\)
32.

Given that \(\sqrt{128}+\sqrt{18}-\sqrt{K} = 7\sqrt{2}\), find K,

A. 8

B. 16

C. 32

D. 48

Detailed Solution

\(\sqrt{128} +\sqrt{18}-\sqrt{k}=7\sqrt{2}\\
\sqrt{2\times 64}+\sqrt{9\times 2} - \sqrt{k} = 7\sqrt{2}\\
8\sqrt{2} + 3\sqrt{2} - \sqrt{k} = 7\sqrt{2}; 11\sqrt{2} - \sqrt{k} = 7\sqrt{2}\\
-\sqrt{k}=7\sqrt{2}-11\sqrt{2}; -\sqrt{k} = -4\sqrt{2}; \sqrt{k}=4\sqrt{2}\\
=\sqrt{4^2\times 2} = \sqrt{16\times 2}; \sqrt{k}=\sqrt{32}; k = 32\)
33.

In the diagram, PQRW is a circle. Line P, V and QR are produced to meet at M, where ∠WMR = 30o and |WM| = |MR| Find the value of x

A. 10o

B. 25o

C. 35o

D. 60o

Detailed Solution

MPQ = PQM = 3x; ∆MPQ
MPQ + PQM + PMQ = 180o; 3x + 3x + 30o = 180o
6x \times 30o = 180o; 6x + 180o - 30o; 6x + 150o
\(x = \frac{150}{6} = 25^{\circ}\)
34.

The table above gives the marks scored by a group of students in a test Use the table to answer the Question below
What is the median mark?

A. 1

B. 2

C. 3

D. 4

Detailed Solution

Median = 0, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5
Median mark = \(\frac{3+3}{2} = \frac{6}{2} = 3\)
35.

The table above gives the marks scored by a group of students in a test Use the table to answer the Question below
What is the probability of selecting a student from the group that scored 2 or 3?

A. \(\frac{1}{11}\)

B. \(\frac{5}{22}\)

C. \(\frac{7}{22}\)

D. \(\frac{6}{11}\)

Detailed Solution

Prob (2 or 3) = prob(2) + prob(3)
Prob (mark 2) \(=\frac{7}{22}\) + Prob(mark 3) = \(\frac{5}{22}\)
Prob(2 or 3) \(=\frac{7}{22}+\frac{5}{22}=\frac{12}{22}=\frac{6}{11}\)
36.

Find the range of values of x for which\(\frac{x+2}{4}-\frac{x+1}{3}>\frac{1}{2}\)

A. x > 4

B. x > -4

C. x < 4

D. x < -4

Detailed Solution

\(\frac{x+2}{4}-\frac{x+1}{3}>\frac{1}{2}\\
\frac{3(x+2)-4(x+1)>6}{12}; 3x + 6 – 4x – 4 > 6\
-x +2>6; -x > 4; x < -4\)
37.

A boy walks 800m in 20 minutes. Calculate his average speed in km per hour

A. 2.4

B. 4

C. 16

D. 24

Detailed Solution

\(Average \hspace{1mm}speed = \frac{Distance}{Time\hspace{1mm} taken}\\
Distance = 800m = \frac{800}{1000}km = 0.8km\\
Time\hspace{1mm}taken = 20\hspace{1mm}minutes = \frac{20}{60}hr=\frac{1}{3}hr\\Average \hspace{1mm} speed = \left(0.8\div \frac{1}{3}\right)km/hr = (0.8\times3)km/hr\\=2.4km/hr\)
38.

Simplify \(\frac{2}{a+b}-\frac{1}{a-b}\)

A. \(\frac{3}{a+b}\)

B. \(\frac{a-3b}{a^2-b^2}\)

C. \(\frac{3a-b}{a^2 – b^2}\)

D. \(\frac{a-3b}{a^2+b^2}\)

Detailed Solution

Simplify \(\frac{2}{a+b}-\frac{1}{a-b}; \frac{2(a-b)-1(a+b)}{(a+b)(a-b)}\)

= \(\frac{2a-2b-a-b}{(a+b)(a-b)}\)

= \(\frac{a-3b}{a^2 - ab + ab - b^2}\)

= \(\frac{a-3b}{a^2-b^2}\)
39.

The diagram is a circle centre O. Find the value of x

A. 30o

B. 50o

C. 61o

D. 78o

E. 65.5\(^{\circ}\)

Detailed Solution

∠PQR (Reflex) = 360° – 68° = 292°
∠PQR = 2∠PQR
292° = 4x + 30°
4x = 292 – 30 = 262
\(x = \frac{262}{4}=65.5°\)
40.

Use the graph to answer the Question below
What are the roots of the equation x2 + 3x - 4 = 0?

A. 1, 4

B. -1, -4

C. -1, 4

D. -4, 1

Detailed Solution

x2 + 3x – 4 = 0 has roots value at the curve makes touches with the x – axis. The curve contact is at x = -4 and +1.