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Mathematics
WAEC / WASSCE 2020
Permutations, Combinations & Probability
Solution
A die was rolled a number of times. The outcomes are as shown in the table
Number
1
2
3
4
5
6
Outcomes
32
m
25
40
28
45
If the probability of obtaining 2 is 0.15, find the:
(a) value of m;
(b) number of times the die was rolled;
(c) probability of obtaining an even number.
medium Difficulty
Verified Correct Answer: Option
Step-by-Step Mathematical Solution
Pr(2) = 0.15
\(\frac{m}{32 + m + 25 + 40 + 28 + 45}\) = 0.15
\(\frac{m}{m + 170}\) = 0.15
m = 0.15(m + 170)
m = 0.15m + 25.5
m - 0.15m = 25.5
\(\frac{0.85m}{0.85} = \frac{25.5}{0.85}\)
m = 30
(b) Number of time
= 32 + 30 + 25 + 40 + 28 + 45
= 200 times
(c) Pr(even number) = \(\frac{30 + 40 + 45}{200}\)
= \(\frac{115}{200}\)
= \(\frac{23}{40}\)
Source: Myschool Past Questions Archive (Record #58710)
Mathematics
WAEC / WASSCE 2020
Trigonometry, Elevation & Bearings
Solution
(a) Copy and complete the table of values for the relation y = 3 sin 2x.
x
o\(^o\)
15\(^o\)
30\(^o\)
45\(^o\)
60\(^o\)
75\(^o\)
90\(^o\)
105\(^o\)
120\(^o\)
135\(^o\)
\(^o\)
y
0.0
1.5
-2.6
(b) Using a scale of 2 cm to 15^\circ on the x-axis and 2cm to I unit on the y-axis, draw the graph of y = 3 sin 2x for 0^\circ \(\geq\) x \(\geq\) 150^\circ.
(c) Use the graph to find the truth set of;
(i) 3 sin 2x + 2 = 0;
(ii ) \(\frac{3}{2}\) sin 2x = 0.25.
medium Difficulty
Verified Correct Answer: Option
Step-by-Step Mathematical Solution
x
o\(^o\)
15\(^o\)
30\(^o\)
45\(^o\)
60\(^o\)
75\(^o\)
90\(^o\)
105\(^o\)
120\(^o\)
135\(^o\)
\(^o\)
y
0.0
1.5
2.6
2.1
2.6
1.5
0
- 1.5
- 2.6
- 3
-2.6
y = 35m\(^2\)x
when x = 15\(^o\)
y = 3 sin = (15\(^o\))
y = sin 30\(^o\)
y = 3 x \(\frac{1}{2}\) = 1.5
When x = 30\(^o\)
y = 3 sin 2(30\(^o\))
y = 3 sin 60\(^o\) = 2.6
When x = 45\(^o\)
y = 3sin45\(^o\)
= 2.1
When x = 60\(^o\)
y = 3 sin 2(60\(^o\))
= 2 sin 120\(^o\)
= 2.6
When x = 75\(^o\)
y = 3 sin 2(75\(^o\))
= 3 sin 150\(^o\)
= 1.5
When x = 90\(^o\)
y = 3 sin 2(90\(^o\))
= 3 sin 180\(^o\)
= 0
When x = 105\(^o\)
y = 3 sin 2(105\(^o\))
= sin 210\(^o\)
= -1.5
When x = 120\(^o\)
y = 3 sin 2(120\(^o\))
= 3 sin 240\(^o\)
= -2.6
When x = 135\(^o\)
y = 3 sin 2(135\(^o\))
y = 3 sin 270\(^o\)
y = -3
(b
SEE THE GRAPH ABOVE...
(c)(i) 113
(ii) 3\(^o\) and 82\(^o\)
Source: Myschool Past Questions Archive (Record #58711)
Mathematics
WAEC / WASSCE 2020
Mensuration (Areas, Perimeters & Volumes)
Diagram
Solution
(a) The diagram shows a wooden structure in the form of a cone, mounted on a hemispherical base. The vertical height of the cone is 48 m and the base radius is 14. Calculate, correct to three significant figures, the surface area of the structure, [Take \(\pi = \frac{22}{7}\)]
(b) Five years ago, Musah was twice as old as Sesay. If the sum of their ages is 100, find Sesay's present age.
Attached Figure / Diagram
medium Difficulty
Verified Correct Answer: Option
Step-by-Step Mathematical Solution
Surface Area of the structure = curved surface area of cone + surface area of hemisphere = \(\pi rl + 2 \pi r^2\)
But slant height l = l\(^2\) = 48\(^2\) + 14\(^2\)
l\(^2\) = 2500
l = \(\sqrt{2500}\) = 50
Surface Area of the structure = \(\pi rl + 2 \pi r^2\) = \(\frac{22}{7}\) x 14 x 50 + 2 x \(\frac{22}{7}\) x 14 x 14
= 3432.0m\(^2\) ≈ 3430m\(^2\) to 3 s.f
(b) Let Musah age be M
Let Sesay be S
M - 5 = 2(S - 5) ......(i)
M + S = 100 ......(ii)
From eqn ii) M = 100 - S
By substitution, 100 - S - 5 = 2(S - 5)
95 - S = 2S - 10
3S = 105
\(\frac{3S}{3} = \frac{105}{3}\)
S = 35
Therefore, Sesay's present age is 35 years
Source: Myschool Past Questions Archive (Record #58712)
Mathematics
WAEC / WASSCE 2020
Sequences & Series (AP & GP)
Solution
(a) Ms. Maureen spent \(\frac{1}{4}\) of her monthly income at a shopping mall, \(\frac{1}{3}\) at an open market and \(\frac{2}{5}\) of the remaining amount at a Mechanic workshop. If she had N222,000.00 left, find:
(i) her monthly income.
(ii) the amount spent at the open market.
(b) The third term of an Arithmetic Progression (A. P.) is 4m - 2n. If the ninth term of the progression is 2m - 8n. find the common difference in terms of m and n.
medium Difficulty
Verified Correct Answer: Option
Step-by-Step Mathematical Solution
(a) Let the salary be x
Shopping mall = \(\frac{1}{4}\) x \(x = \frac{x}{4}\)
Open market = \(\frac{1}{3} \times x = \frac{x}{3}\)
The remainder x - [\(\frac{x}{4} + \frac{x}{3}\)]
= x - [\(\frac{3x + 4x}{12}\)]
= \(\frac{x}{1} - \frac{7x}{12}\)
= \(\frac{12x - 7x}{12}\)
= \(\frac{5x}{12}\)
mechanic = \(\frac{2}{5} \times \frac{5x}{12} = \frac{x}{6}\)
\(\frac{x}{6} + \frac{x}{3} + \frac{x}{4}\) + 225,00 = x
\(\frac{2x + 4x + 3x}{12}\) + 225,000
\(\frac{9x}{12}\) + 225,000 = x
225,000 = \(\frac{x}{1} = \frac{9x}{12}\)
225,000 = \(\frac{12x - 9x}{12}\)
225,000 = \(\frac{3x}{12}\)
\(\frac{225,000 \times 12}{3}\) = x
N900,000 = x
(i) Her monthly income = N900,000
(ii) Amount in open market
= \(\frac{N900,000}{3}\)
= N300,000
(b) T\(_3\) = 4m - 2n
T\(_9\) = 2m - 8n
a + 2d = 4m - 2n .....(i)
a + 8d = 2m - 8n ......(ii)
a + 8d = 2m - 8n
-(a + 2d = 4m - 2n
\(\overline{6d = -2m - 6n}\)
6d = -2(m + 3n)
d = -\(\frac{m + 3n}{3}\)
Common difference = -\(\frac{m + 3n}{3}\)
Source: Myschool Past Questions Archive (Record #58713)
Mathematics
WAEC / WASSCE 2020
Trigonometry, Elevation & Bearings
Solution
(a) Two cyclists X and Y leave town Q at the same time. Cyclist X travels at the rate of 5 km/h on a bearing of 049^\circ and cyclist Y travels at the rate of 9 km/h on a bearing of 319^\circ.
(a) Illustrate the information on a diagram.
(b) After travelling for two hours, calculate. correct to the nearest whole number, the:
(i) distance between cyclist X and Y;
(ii) bearing of cyclist X from Y.
(c) Find the average speed at which cyclist X will get to Y in 4 hours.
medium Difficulty
Verified Correct Answer: Option
Step-by-Step Mathematical Solution
(a) diagram above
(b)(i) m\(^2\) = 5\(^2\) + 9\(^2\)
m\(^2\) = 25 + 81
m\(^2\) = 106
m = \(\sqrt{106}\) = 10.296 km/hr
Speed = \(\frac{distance}{times}\)
distance = speed x time
= 10.296 x 2
= 21km
(b)(ii)
tan\(\theta\) = \(\frac{9km/hr}{5km/hr}\)
tan\(\theta\) = 1.8
\(\theta\) = tan\(^{-1}\)
\(\theta\) = 60.9\(^o\)
the bearing of cyclist x from y
90\(^o\) + 19.9\(^o\) = 109.9\(^o\)
= 110\(^o\)
(c) The average speed = \(\frac{distance }{time}\)
= \(\frac{21}{4}\)km
= 5km/her
Source: Myschool Past Questions Archive (Record #58714)
Mathematics
WAEC / WASSCE 2020
Statistics (Data Representation, Central Tendency & Dispersion)
Solution
The table shows the distribution of marks obtained by students in an examination.
Marks (%)
0 - 9
10 - 19
20 - 29
30 - 39
40 - 49
50 - 59
60 - 69
70 - 79
80 - 89
90 - 99
Frequency
7
11
17
20
29
34
30
25
21
6
(a) Construct a cumulative frequency table for the distribution.
(b) Draw the cumulative frequency curve for the distribution.
(c) Using the curve, find correct to one decimal place, the:
(i) median mark;
(ii) lowest mark for the distinction if 5% of the students passed with distinction
medium Difficulty
Verified Correct Answer: Option
Step-by-Step Mathematical Solution
Marks
Upper
Class
Boundary
Frequency (F)
Cumulative
Frequency (F)
(CF)
0 - 9
10 - 19
20 - 29
30 - 39
40 - 49
50 - 59
60 - 69
70 - 79
80 - 89
90 - 99
9.5
19.5
29.5
39.5
49.5
59.5
69.5
79.5
89.5
99.5
7
11
17
20
29
34
30
25
21
6
7
18
35
55
84
118
148
173
194
200
(b)
(c) (I) Median Mark = 54.5
(ii) Lowest mark, if 5% of the students passed = 14
Source: Myschool Past Questions Archive (Record #58715)
Mathematics
WAEC / WASSCE 2020
Coordinate Geometry
Diagram
Solution
(a) In the diagram, MNPQ is a circle with centre O, |MN| = |NP| and < OMN = 50^\circ. Find:
(I) < MNP
(ii) < POQ
(b) Find the equation of the line which has the same gradient as 8y + 4xy = 24 and passes through the point (-8, 12)
Attached Figure / Diagram
medium Difficulty
Verified Correct Answer: Option
Step-by-Step Mathematical Solution
(a)
(i)
< NPQ = 180\(^o\) - 50\(^o\) = 130\(^o\)
< MNP = 130\(^o\) - 90\(^o\) = 40\(^o\)
< NMP = 40\(^o\) (Isolceles triangle)
< MNP = 180\(^o\) - (40\(^o\) + 40\(^o\))
= 180\(^o\) - 80\(^o\) = 100\(^o\)
(ii) < OPQ = 90\(^o\)(50\(^o\) - 40\(^o\)) = 80\(^o\)
< OPQ = 80\(^o\) (Isoseles triangle)
< POQ = 180\(^o\) (80\(^o\) + 80\(^o\))
180\(^o\) - 160\(^o\) = 20\(^o\)
(b) 8y + 4x = 24
\(\frac{8y}{8} = \frac{-4y}{8} + \frac{24}{8}\)
y = \(\frac{-1}{2}x + 6\)
m = \(\frac{-1}{2}\)
The equation will give
\(\frac{y - 12}{x + 8} = \frac{-1}{2}\)
2y - 24 = x - 8
2y = - x - 8 + 24
2y = -x + 16
Source: Myschool Past Questions Archive (Record #58716)
Mathematics
WAEC / WASSCE 2020
Indices, Logarithms & Surds
Diagram
Solution
(a) In the diagram, AB is a tangent to the circle with centre O, and COB is a straight line. If CD//AB and < ABE = 40^\circ, find: < ODE.
(b) ABCD is a parallelogram in which |\(\overline{CD}\)| = 7 cm, I\(\overline{AD}\)I = 5 cm and < ADC= 125^\circ.
(i) Illustrate the information in a diagram.
(ii) Find, correct to one decimal place, the area of the parallelogram.
(c) If x = \(\frac{1}{2}\)(1 - \(\sqrt{2}\)). Evaluate (2x\(^2\) - 2x).
Attached Figure / Diagram
medium Difficulty
Verified Correct Answer: Option
Step-by-Step Mathematical Solution
< AOB = 108\(^o\) - (90\(^o\) + 40\(^o\))
= 180\(^o\) - 130\(^o\) = 50\(^o\)
< DCO = 40\(^o\) (Alternate angle)
< ODE = \(\frac{180^o - 80^o}{2}\) = \(\frac{100^o}{2}\)
= 50\(^o\)
(b)(i)
(b)(ii) Area of the parallelogram
= ab sin \(\theta\)
= 5cm x 7cm sin 125\(^3\)
= 35 sin 125
= 28.7cm\(^2\)
(c)
x = \(\frac{1}{2}(1 - \sqrt{2})\)
evaluate (2x\(^2\) - 2x)
= 2[\(\frac{1}{2}(1 - \sqrt{2})^2\)] - 2[\(\frac{1}{2} (1 - \sqrt{2}\))]
= 2[\(\frac{1}{4}(1 - 2\sqrt{2} + 2)\)] - 1 + \(\sqrt{2}\)
= 2[\(\frac{1}{4}(3 - 2\sqrt{2})\) - 1 + \(\sqrt{2}\)]
2[\(\frac{3}{4} - \frac{1}{2} \sqrt{2} - 1 + \sqrt{2}\)]
= \(\frac{3}{2} - \sqrt{2} - 2 + 2\sqrt{2}\)
= \(\frac{1}{2} + \sqrt{2}\)
Source: Myschool Past Questions Archive (Record #58717)
Biology
UTME / JAMB 2020
Variety of Organisms & Classification of Living Things
Diagram
Solution
Use the diagram to answer the question.
The structure labelled i is
Attached Figure / Diagram
A
photosensitive
B
radiosensitive
C
chemoreceptive
D
tactile
medium Difficulty
Verified Correct Answer: Option D
Biological Concept & Syllabus Guide
The part labeled I is commonly called tactile hairs, sinus hairs, whiskers, or vibrissae. ( are the long, specialized hairs found on the face and nose of rodents like rats, etc, and other animals like pussy cats)
Source: Official Exam / Past Question Archive
Biology
WAEC / WASSCE 2020
Variation & Genetics (Heredity)
Solution
Study Specimens P, Q and R and answer questions 4(a) to 4(d).
(a) Use the information below to complete the following table. (i) Add two drops of specimen P into a beaker containing water, leave it undisturbed and note the time it completely disperses in water. (ii) Add a leveled teaspoonful of specimen Q into another beaker containing water, stir for one second and note the time it takes to completely dissolve. (iii) Cut open specimen R and note the time the odor was perceived. (iv) Give the medium of spread for each of the tests in 4(a)(i) to 4(a) i).
(v) Name the sense organ in humans involved in each of the observations in 4(a)(i) to 4(a)(iii).
specimen
Test
Observation time(sec)
Medium of spread
sense organ
(b) Name the biological phenomenon that occurred in 4(a)(iii).
(c) State two factors each that will increase the rate of the phenomenon named in 4(b) for each of the activities in 4(a)(i). (ii) and (iii)
(i) _____________ (ii) _____________ (iii) _____________
(d) Gently place your thumb on the inked stamp pad provided. (i) Neatly thumbprint clearly showing the pattern in the box below.
(ii) Name the type of pattern in the fingerprint in 4(e)(i).
(iii) List three other types of fingerprints. (iv) State three advantages of fingerprints.
(v) What type of variation is fingerprint?
medium Difficulty
Verified Correct Answer: Option
Biological Concept & Syllabus Guide
specimen
Test
Observation time(sec)
Medium of spread
sense organ
p
2 drops of specimen p
+ water
5 - 10
liquid / water
Eye(s)
Q
Leveled teaspoonful of
specimen Q + water
300 - 1800
liquid / water
Eye(s)
R
Specimen R was cut open
0.1 - 2
Gas / Air
Nose
(b) (b) Biological Phenomenon that Occurred: Diffusion.
(c) Factors that will Increase the Rate of Phenomenon for each Activities:
(i)-Decreased concentration of the potassium permanganate: -Shaking/stirring/agitating: -Increased.temperature/heat.
(ii)-Grinding/increasing the surface area of Specimen Q to reduce the molecular/grain size;
-Decreased quantity of Specimen Q; Shaking/stirring/agitating;-Increased temperature/heat.
(iii) -Increased air current/breeze/fan; Increased quantity of specimen R;-increased temperature/heat.
Other types of fingerprints:-Whorl Loop;-Arch, Contour,- etc. (any other three types different from the One or the thumbprint).
(V) Advantages ot Fingerprints: or crime detectton.securing documents.-Highly accurate/secure.-Unique/non-transferrable.
-identification,-Data base.-Genetic engineering.
Most economical technique/cost effective.Easy to use/ease of use.
-Use ot smalt storage space/little storage space needed.-Provides accountability (biometric proof to show person was there when an event occurred).
(V) Type of Variation: Discontinuous/Morphological.
Source: Official Exam / Past Question Archive
Biology
UTME / JAMB 2020
Nervous, Hormonal Coordination & Sense Organs
Solution
The hormone which regulates the amount of glucose in the blood is called?
A
Adrenalin
B
Auxin
C
Insulin
D
Thyroxine
medium Difficulty
Verified Correct Answer: Option C
Biological Concept & Syllabus Guide
Insulin helps control blood glucose levels by signaling the liver and muscle and fat cells to take in glucose from the blood.
Source: Myschool Past Questions Archive (Record #56755)
Biology
UTME / JAMB 2020
Excretion & Homeostasis
Solution
Deamination occurs in the?
A
Kidney
B
Pancreas
C
Spleen
D
Liver
medium Difficulty
Verified Correct Answer: Option D
Biological Concept & Syllabus Guide
Deamination is used to break down amino acids for energy, and occurs primarily in the liver.
Source: Myschool Past Questions Archive (Record #56756)
Biology
UTME / JAMB 2020
Basic Ecological Concepts, Ecosystems & Biomes
Solution
In an agricultural ecosystem, the biotic component consist of
A
crops, pests and beneficial insects
B
crops, temperature and humidity
C
pests, beneficial insects and water
D
crops, water and soil
medium Difficulty
Verified Correct Answer: Option A
Biological Concept & Syllabus Guide
The living components of an ecosystem are called the biotic components, option A has all living components.
Source: Myschool Past Questions Archive (Record #56760)
Biology
UTME / JAMB 2020
Nutrition in Plants & Animals (Photosynthesis & Food Substances)
Solution
Epiphytes growing on the branches of trees provide an example of the relationship known as?
A
parasitism
B
commensalism
C
saprophytism
D
holophytism
medium Difficulty
Verified Correct Answer: Option B
Biological Concept & Syllabus Guide
Commensalism is a type of symbiosis, specifically, a biological relationship in which one specie benefits from an interaction, while the host species is neither positively or negatively affected to any tangible degree.
Source: Myschool Past Questions Archive (Record #56762)
Biology
UTME / JAMB 2020
Variety of Organisms & Classification of Living Things
Solution
The hypha of rhizopus is said to be non-septate because it
A
does not contain chloropyll
B
has no cross wall
C
is vacuoled
D
stores oil globus
medium Difficulty
Verified Correct Answer: Option B
Biological Concept & Syllabus Guide
Hyphae that have walls between the cells are called septate hyphae; hyphae that lack walls and cell membranes between the cells are called nonseptate or coenocytic hyphae)
Source: Myschool Past Questions Archive (Record #56766)