Mathematics 2020 Past Questions | JAMB
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.
16. A crate of soft drinks contains 10 bottle of Coca-Cola 8 of Fanta and 6 of Sprite. If one bottle is selected at random, what is the probability that it is Not a Coca-Cola bottle?
- A. 5/12
- B. 1/3
- C. 3/4
- D. 7/12
Correct Option: Answer is D
Solution:Coca-Cola = 10 bottles, Fanta = 8 bottles, Spirite = 6 bottles
Total = 24
P(Coca-Cola) = \(\frac{10}{24}\); P(not Coca-Cola)
1 – \(\frac{10}{24}\)
\(\frac{24 – 10}{24} = \frac{14}{24} = \frac{7}{12}\)
17. In this figure, PQ = PR = PS and SRT = 68o. Find QPS
- A. 136o
- B. 124o
- C. 112o
- D. 68o
Correct Option: Answer is A
Solution:
2y + 2x + QPS = 360o
i.e. (y + x) + QPS = 360o
QPS = 360o – 2 (y + x)
But x + y + 68o = 180o
There; x + y = 180o – 68o = 112o
QPS = 360 – 2(112o)
= 360o – 224 = 136o
18. Find the gradient of the line passing through the points (-2, 0) and (0, 4)
- A. 2
- B. -4
- C. -2
- D. 4
Correct Option: Answer is A
Solution:
Given (-2, 0) ans (0, -4). Gradient = −4−0/0−(−2)
= −4/2 = -2
19. Find the equation of the line through the points (5, 7) parallel to the line 7x + 5y = 12.
- A. 5x + 7y = 120
- B. 7x + 5y = 70
- C. x + y = 7
- D. 15x + 17y = 90
Correct Option: Answer is B
20. If N225.00 yields N27.00 in x years simple interest at the rate of 4% per annum, find x.
- A. 3
- B. 4
- C. 12
- D. 17
Correct Option: Answer is A
Solution:
Principal = N225.00; Interest = N27.00; Time = X; Rate = 4%
∴ S.I = PRT/100
27 = 225 x 4 x X
100
=> 2700 = 900X
∴ X = 2700/900
X= 3 years
21. Calculate the standard deviation of the following data: 7, 8, 9, 10, 11, 12, 13
- A. 2
- B. 4
- C. 12
- D. 17
Correct Option: Answer is A
Solution:
x | x – x | (x – x)2 |
7 8 9 10 11 12 13
| -3 -2 -1 0 1 2 3
| 9 4 1 1 0 4 9 ————– 28
|
- Standard Deviation SD = ∑(x−x)2/N=∑d2/N=√28/7 = √4 = 2
22. A number is selected at random between 20 and 30, both numbers inclusive. Find the probability that the number is a prime.
- A. 2/11
- B. 5/11
- C. 6/11
- D. 8/11
Correct Option: Answer is A
Solution:
Possible outcomes are 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. Prime numbers have only two factors, itself and 1. The prime numbers among the group are 23, 29.
The probability of choosing a prime number
= Number of Prime/ No. of Total Possible Outcome
= 2/11
23. The equation of the line in the graph is
- A. 3y = 3x + 12
- B. 3y = 3x + 12
- C. 3y = -4x + 12
- D. 3y = -4x + 9
Correct Option: Answer is C
Solution:
24. Express the product of 0.0014 and 0.011 in standard form
- A. 1.54 x 10−2
- B. 1.54 x 10−3
- C. 1.54 x 10−2
- D. 1.54 x 10−5
Correct Option: Answer is D
Solution:
- = 1.4 x 10−3 + 1.1 x 10−2
- = 1.4 x 1.1 + 10−3 + 10−2 = 1.54 x 10−5
25. A school boy lying on the ground 30m away from the foot of a water tank towel observes that the angle of elevation of the top of the tank is 60o. Calculate the height of the tank.
- A. 60√3m
- B. 30√3m
- C. 20√3m
- D. 10√3m
Correct Option: Answer is B
hΔ
30m
h = 30 tan 60
= 30–√3
26. Find the simple interest rate percent annum at which N1000 accumulates to N1240 in 3 years.
- A. 6%
- B. 8%
- C. 10%
- D. 12%
Correct Option: Answer is B
S.I = PRT/100
I = 1,240 – 1000 240
P = 1000; R = ? T = 3
∴ 240 = 240 x 100/ 1000 x 3
= 8%
27. The pie chart shows the income of a civil servant in month. If his monthly income is N6,000. Find his monthly basic salary.
- A. N2,050
- B. N2600
- C. N3,100
- D. N3,450
Correct Option: Answer is A
- 360o- (60o + 60o + 67 + 50 = 237o)
- 360o- 237 = 130o
- Basic Salary = 123/360XN6000/1= N2,050
28. If x is positive real number, find the range of values for which 1/3x + 1/2> 1/4x
- A. x > -1/6
- B. x > 0
- C. 0 < x < 6
- D. 0 < x <1/6
Correct Option: Answer is A
29. Find the value of x if = √2 / x + √2 = 1/ x – √2
- A. 3√2 + 4
- B. 3√2 – 4
- C. 3 – 2√2
- D. 4 + 2√2
Correct Option: Answer is D
The lenght of Arc AB = \(\frac{Q}{360}\) 2\(\pi\)r
= \(\frac{48}{360}\) x 2\(\frac{22}{7}\) x 10.5 = \(\frac{48}{360}\) x 2\(\frac{22}{7}\) x \(\frac{21}{2}\)
= \(\frac{4 \times 22 \times 3}{30} \times \frac{88}{10}\) = 8.8cm
Perimeter = 8.8 + 2r = 8.8 + 2r
= 8.8 + 2(10.5)
= 8.8 + 21
= 29.8cm
30. A binary operation x is defined by a x b = ab. If a x 2 = 2 – a, find the possible values of a?
- A. 1, -2
- B. 2, -1
- C. 2, -2
- D. 1, -1
Correct Option: Answer is A