Mathematics 2020 Past Questions | WAEC
Study the following Mathematics past questions and answers for JAMB, WAEC NECO and Post-JAMB. Get prepared with official past questions and answers for upcoming examinations.
31. In the diagram, PS¯/SR¯, PS¯/TR¯, QS¯/UR¯, PS¯= 15cm, SR¯= 8cm, PS¯ = 10cm and area of △ SUR = 24cm2. Calculate the area of PTRS.
- A. 40 cm2
- B. 48 cm2
- C. 80 cm2
D. 120 cm2
Correct Option: Answer is C
Area PTRS = 10cm x 8cm
= 80cm
32. In the diagram, PQR is a circle with centre O. If < OPQ = 48o, find the value of m
- A. 96o
- B. 90o
- C. 68o
- D. 42o
Correct Option: Answer is A
Q
< OQP = 48o (base angles of isoceles △)
m = 48o + 48o = 96o (exterior angle of a △)
33. The pie chart shows the population of men, women, and children in a city. If the population of the city is 1,800,000, how many men are in the city?
- A. 845,000
- B. 600,000
- C. 355,000
D. 250,000
Correct Option: Answer is B
Angle of Men = 360o – (120 + 169)
= 360o – 289o = 71o
Number of men = 71/360 x 1800,000
= 355,000
34. The mean of the numbers 15, 21, 17, 26, 18, and 29 is 21. Calculate the standard deviation
- A. 9
- B. 6
- C. 5
- D. 0
Correct Option: Answer is C
35. In the diagram, O is the centre of the circle. SOQ is the diameter and < SRP = 37o. Find < PSQ.
- A. 127o
- B. 65o
- C. 53o
- D. 37o
Correct Option: Answer is C
< PSQ = 180o – (37o + 90o)
= 180o – 127o = 53o
36. Find the sum of the interior angle of a pentagon.
- A. 340o
- B. 350o
- C. 540o
- D. 550o
Correct Option: Answer is C
- Sum of interior angles = (n − 2) × 180∘
= (5 – 2) x 180o
= (5 – 2) x 180o = 3 x 180o
= 540o
37. The diameter of a sphere is 12 cm. Calculate, correct of the nearest cm3, the volume of the sphere, [Take π=22/7]
A. 903 cm3- B. 904 cm3
- C. 905 cm3
- D. 906 cm3
Correct Option: Answer is C
Volume of Sphere (V) = 4/3 πr3
Diameter = radius x 2, r = =12/2 6cm
V = 4/3 x 22/7 x 6 x 6 x 6 = 905.14 = 905cm3
38. A box contains 12 identical balls of which 5 are red, 4 blue, and the rest are green. If a ball is selected at random from the box, what is the probability that it is green?
- A. 3/4
- B. 1/2
- C. 1/3
- D. 1/4
Correct Option: Answer is D
No. of red = 5
No. of blue = 4
No. of green = 3
Total = 12
Pr(Green) = 3/12=1/4
39. A box contains 12 identical balls of which 5 are red, 4 blue, and the rest are green. If two balls are selected at random one after the other with replacement, what is the probability that both are red?
- A. 25/144
- B. 5/33
- C. 5/6
- D. 103/132
Correct Option: Answer is A
- Pr (R)= 5/12
- Pr (B)= 4/12
- Pr (G)= 3/12
- Therefore:
- Pr (RR)= 5/12 x 5/12 x 5/12 =25/144
40. In the diagram PQ is a straight line. If m = 1/2(x + y + z), find value of m.
- A. 45o
- B. 60o
- C. 90o
- D. 100o
Correct Option: Answer is B
x + y + m + 2 = 180\(^o\)
\(\frac{x + y + 2}{2} + \frac{m}{2}\) = 90\(^o\)
m + \(\frac{m}{2} = 90^o\)
3m = 2 x 90\(^o\)
\(\frac{3m}{3} = \frac{180^o}{3}\)
m = 60\(^o\)
41.
x | 6.20 | 6.85 | 7.50 |
y | 3.90 | 5.20 | 6.50 |
The points on a linear graph are as shown in the table. Find the gradient (slope) of the line.
- A. 2 1/2
- B. 2
- C. 1
- D. 1/2
Correct Option: Answer is B
42. In the diagram, O is the centre of the circle, PQ¯and RS¯are tangents to the circle. Find the value of (m + n).
- A. 120o
- B. 90o
- C. 75o
- D. 60o
Correct Option: Answer is B
m + n + 90o + 180o (sum of angle in a △)
m + n = 180o – 90o
m + n =90o
43. Which of the following is not a sufficient condition for two triangles to be congruent?
- A. AAS
- B. SSS
- C. SAS
- D. SSA
Correct Option: Answer is D
44. A woman received a discount of 20% on a piece of cloth she purchased from a shop. If she paid $525.00, what was the original price?
- A. $675.25
- B. $660.25
- C. $656.25
- D. $616.25
Correct Option: Answer is C
Let the cost of the cloth be x
Then 20% of x =20/100x =1/5x
x/5=x-525
= 5(x-525)=x
5x – 2625 =x
X=2625/4 = 656.25
45. The interquartile range of distribution is 7. If the 25th percentile is 16, find the upper quartile.
- A. 35
- B. 30
- C. 23
- D. 9
Correct Option: Answer is C
Q3 = ¾(n + 1)th
Q3 -Q1 =7
Q3 -16 =7
Q3 = 7 +16
=23