JAMB Mathematics 2003 past questions and answers

49 questions. Try each one, then open the answer to check yourself and read the explanation.

Question 1

Logarithms

Evaluate log√24 + log½16 − log432

  1. A.−5.5
  2. B.−2.5
  3. C.2.5
  4. D.5.5
Show the answer and explanation

Answer: B (−2.5)

Explanation

log√24 = 4 because (√2)4 = 4; log½16 = −4; log432 = 5/2. So 4 − 4 − 2.5 = −2.5.

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Question 2

Number Bases

Simplify 2134 × 234

  1. A.103114
  2. B.103214
  3. C.122314
  4. D.132114
Show the answer and explanation

Answer: C (122314)

Explanation

2134 = 39 and 234 = 11 in base ten, so the product is 429. Converting 429 to base four gives 122314.

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Question 3

Sets

In a class of 40 students, 32 offer Mathematics, 24 offer Physics. How many offer both Mathemaics and Physics?

  1. A.20
  2. B.16
  3. C.8
  4. D.4
Show the answer and explanation

Answer: B (16)

Explanation

Everyone offers at least one subject, so both = 32 + 24 − 40 = 16.

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Question 5

Commercial Arithmetic

A woman buys 270 oranges for N1,800.00 and sells at 5 for N40.00. What is her profit?

  1. A.N2,160.00
  2. B.N1,620.00
  3. C.630.00
  4. D.N360.00
Show the answer and explanation

Answer: D (N360.00)

Explanation

She sells 270 ÷ 5 = 54 lots at N40, getting N2,160. Profit = 2,160 − 1,800 = N360.

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Question 6

Fractions, Decimals and Approximation

Simplify 1 − (2⅓ × 1¼) + 3/5

  1. A.−1 1/15
  2. B.−1 19/60
  3. C.−2 7/15
  4. D.−2 31/60
Show the answer and explanation

Answer: B (−1 19/60)

Explanation

2⅓ × 1¼ = 7/3 × 5/4 = 35/12. Then 1 − 35/12 + 3/5 = (60 − 175 + 36)/60 = −79/60 = −1 19/60.

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Question 7

Surds

Simplify (√98 − √50)/√32

  1. A.3
  2. B.1
  3. C.½
  4. D.¼
Show the answer and explanation

Answer: C (½)

Explanation

√98 = 7√2, √50 = 5√2 and √32 = 4√2, so the value is 2√2/(4√2) = ½.

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Question 8

Ratio, Percentages and Rates

A cinema hall contains a certain number of people. If 22½% are children, 47½% are men and 84 are women, find the number of men in the hall.

  1. A.63
  2. B.84
  3. C.113
  4. D.133
Show the answer and explanation

Answer: D (133)

Explanation

Women are 100 − 22½ − 47½ = 30% of the hall, so the hall holds 84 ÷ 0.3 = 280 people. Men = 47½% of 280 = 133.

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Question 9

Indices

If 92x − 1/27x+1 = 1, find the value of x.

  1. A.8
  2. B.5
  3. C.3
  4. D.2
Show the answer and explanation

Answer: B (5)

Explanation

92x − 1 = 27x + 1 means 34x − 2 = 33x + 3, so 4x − 2 = 3x + 3 and x = 5.

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Question 10

Number Bases

The sum of four numbers is 12145. What is the average expressed in base five?

  1. A.114
  2. B.141
  3. C.401
  4. D.411
Show the answer and explanation

Answer: B (141)

Explanation

12145 = 125 + 50 + 5 + 4 = 184. The average is 184 ÷ 4 = 46, and 46 = 1415.

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Question 11

Sets

Given:
U = {Even numbers between 0 and 30}
P = {Multiples of 6 between 0 and 30}
Q = {Multiples of 4 between 0 and 30}
Find (P∪Q)c

  1. A.{2,10,14,22,26}
  2. B.{0,10,14,22,26}
  3. C.{2,4,14,18,26}
  4. D.{0,2,6,22,26}
Show the answer and explanation

Answer: A ({2,10,14,22,26})

Explanation

P ∪ Q = {4, 6, 8, 12, 16, 18, 20, 24, 28}. The even numbers left over in U are {2, 10, 14, 22, 26}.

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Question 12

Variation

x varies directly as the product of u and v and inversely as their sum. If x = 3 when u = 3 and v = 1, what is the value of x if u = 3 and v = 3?

  1. A.3
  2. B.4
  3. C.6
  4. D.9
Show the answer and explanation

Answer: C (6)

Explanation

x = kuv/(u + v). From 3 = k(3)/4, k = 4. Then x = 4 × 9/6 = 6.

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Question 13

Inequalities

Find the range of the values of x satisfying the inequalities 5 + x ≤ 8 and 13 + x ≥ 7.

  1. A.−3 ≤ x ≤ 3
  2. B.3 ≤ x ≤ 6
  3. C.−6 ≤ x ≤ 3
  4. D.−6 ≤ x ≤ −3
Show the answer and explanation

Answer: C (−6 ≤ x ≤ 3)

Explanation

5 + x ≤ 8 gives x ≤ 3 and 13 + x ≥ 7 gives x ≥ −6, so −6 ≤ x ≤ 3.

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Question 14

Matrices and Determinants

If |−x 2; 4x 1| = |3 3x; 4 −5|, find the value of x. (Each is a 2 × 2 determinant written row by row.)

  1. A.5
  2. B.2
  3. C.−2
  4. D.−5
Show the answer and explanation

Answer: D (−5)

Explanation

Left side: −x − 8x = −9x. Right side: −15 − 12x. So −9x = −15 − 12x, 3x = −15 and x = −5.

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Question 15

Graphs of Functions

The graph of the function y = x2 + 4 and a straight line PQ are drawn to solve the equation x2 − 3x + 2 = 0. What is the equation PQ?

  1. A.y = 3x − 2
  2. B.y = 3x + 2
  3. C.y = 3x − 4
  4. D.y = 3x + 4
Show the answer and explanation

Answer: B (y = 3x + 2)

Explanation

x2 − 3x + 2 = 0 can be written x2 + 4 = 3x + 2, so the line is y = 3x + 2.

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Question 16

Variation

The length a person can jump is inversely proportional to his weight. If a 20kg person can jump 1.5m, find the constant proportionality.

  1. A.60
  2. B.30
  3. C.20
  4. D.15
Show the answer and explanation

Answer: B (30)

Explanation

L = k/W, so k = LW = 1.5 × 20 = 30.

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Question 17

Linear and Simultaneous Equations

Find the values of x and y respectively if 3x − 5y + 5 = 0 and 4x − 7y + 8 = 0

  1. A.−5, −4
  2. B.−4, −5
  3. C.4, 5
  4. D.5, 4
Show the answer and explanation

Answer: D (5, 4)

Explanation

Multiply to get 12x − 20y = −20 and 12x − 21y = −24; subtracting gives y = 4. Then 3x = 20 − 5 = 15, so x = 5.

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Question 18

Progressions

Three consecutive terms of a geometric progression are given as n − 2, n and n + 3. Find the common ratio.

  1. A.¼
  2. B.½
  3. C.2/3
  4. D.3/2
Show the answer and explanation

Answer: D (3/2)

Explanation

n2 = (n − 2)(n + 3) = n2 + n − 6, so n = 6. The terms are 4, 6, 9 and the ratio is 6/4 = 3/2.

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Question 19

Inequalities

Triangle OPQ above is the solution to the inequalities

Diagram for this question
  1. A.x + 1 ≥ 0, y + x ≤ 0, y − x ≥ 0
  2. B.y + x ≤ 0, y − x ≥ 0, x − 1 ≥ 0
  3. C.x − 1 ≤ 0, y − x ≥ 0, y + x ≥ 0
  4. D.x − 1 ≤ 0, y + x ≤ 0, y − x ≤ 0
Show the answer and explanation

Answer: A (x + 1 ≥ 0, y + x ≤ 0, y − x ≥ 0)

Explanation

The triangle lies to the right of x = −1 (x + 1 ≥ 0), below the line y + x = 0 and above the line y − x = 0. The point (−0.5, 0) inside it satisfies all three inequalities in A.

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Question 20

Algebraic Expressions

Factorize completely 4abx − 2axy − 12b2x + 6bxy.

  1. A.2x(a − 3b)(2b − y)
  2. B.2x(3b − a)(2b − y)
  3. C.2x(a − 3b)(y − 2b)
  4. D.2x(2b − a)(3b − y)
Show the answer and explanation

Answer: A (2x(a − 3b)(2b − y))

Explanation

Group: 2ax(2b − y) − 6bx(2b − y) = (2ax − 6bx)(2b − y) = 2x(a − 3b)(2b − y).

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Question 21

Matrices and Determinants

A matrix P has an inverse P−1 = (1 −3; 0 1). Find P. (Matrices are written row by row.)

  1. A.(−1 3; 0 −1)
  2. B.(1 3; 0 −1)
  3. C.(1 −3; 0 −1)
  4. D.(1 3; 0 1)
Show the answer and explanation

Answer: D ((1 3; 0 1))

Explanation

P is the inverse of P−1. The determinant of (1 −3; 0 1) is 1, so its inverse is (1 3; 0 1).

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Question 22

Progressions

The sum of the first n terms of an arithmetic progression is 252. If the first term is −16 and the last term is 72, find the number of terms in the series.

  1. A.6
  2. B.7
  3. C.8
  4. D.9
Show the answer and explanation

Answer: D (9)

Explanation

S = n/2 (a + l): 252 = n/2 (−16 + 72) = 28n, so n = 9.

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Question 23

Mensuration of Plane Shapes

An arc of a circle subtends an angle of 30° on the circumference of a circle of radius 21cm. Find the length of the arc. [π = 22/7]

  1. A.11cm
  2. B.22cm
  3. C.44cm
  4. D.66cm
Show the answer and explanation

Answer: B (22cm)

Explanation

The angle at the centre is twice the angle at the circumference, so it is 60°. Arc length = 60/360 × 2 × 22/7 × 21 = 22cm.

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Question 24

Loci

Find the equation of the locus of a point P(x,y) which is euidistant from Q(0,0) and R(2,1).

  1. A.4x + 2y = 5
  2. B.4x − 2y = 5
  3. C.2x + 2y = 5
  4. D.2x + y = 5
Show the answer and explanation

Answer: A (4x + 2y = 5)

Explanation

x2 + y2 = (x − 2)2 + (y − 1)2 gives 0 = −4x + 4 − 2y + 1, so 4x + 2y = 5.

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Question 25

Angles and Polygons

In the diagram above, PQ is parallel to RS. What is the value of α + β + γ?

Diagram for this question
  1. A.360°
  2. B.200°
  3. C.180°
  4. D.90°
Show the answer and explanation

Answer: A (360°)

Explanation

If each slanting line makes angles θ and φ with the horizontal, then α = 90° + θ, γ = 90° + φ and β = 180° − θ − φ. Adding them gives 360°.

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Question 26

Mensuration of Plane Shapes

A trapezium has two parallel sides of length 5cm and 9cm. If the area is 21cm2, find the distance between the parallel sides.

  1. A.3cm
  2. B.4cm
  3. C.6cm
  4. D.7cm
Show the answer and explanation

Answer: A (3cm)

Explanation

Area = ½(5 + 9) × h = 7h = 21, so h = 3cm.

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Question 27

Trigonometry

Which of the following is the graph of sinθ for −π/2 ≤ θ ≤ 3π/2?

Diagram for this question
  1. A.Graph A
  2. B.Graph B
  3. C.Graph C
  4. D.Graph D
Show the answer and explanation

Answer: D (Graph D)

Explanation

sin θ is −1 at −π/2, 0 at 0, 1 at π/2, 0 at π and −1 at 3π/2: it rises through the origin to a peak and then falls. Only graph D has this shape.

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Question 28

Circle Theorems

In the diagram above, O is the centre of the circle, POM is a diameter and ∠MNQ = 42°. Calculate ∠QMP.

Diagram for this question
  1. A.42°
  2. B.48°
  3. C.132°
  4. D.138°
Show the answer and explanation

Answer: B (48°)

Explanation

∠MPQ = ∠MNQ = 42° (angles in the same segment), and ∠MQP = 90° (angle in a semicircle). So ∠QMP = 180° − 90° − 42° = 48°.

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Question 29

Coordinate Geometry

Find the value of p, if the line which passes through (−1, −p) and (−2p, 2) is parallel to the line 2y + 8x − 17 = 0

  1. A.7/6
  2. B.6/7
  3. C.−2/7
  4. D.−6/7
Show the answer and explanation

Answer: B (6/7)

Explanation

The given line has gradient −4. So (2 + p)/(−2p + 1) = −4, giving 2 + p = −4 + 8p, 7p = 6 and p = 6/7.

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Question 30

Bearings

An aeroplane flies due north from airports P to Q and then flies due east to R. If Q is euidistant from P and R, find the bearing of P from R.

  1. A.090°
  2. B.135°
  3. C.225°
  4. D.270°
Show the answer and explanation

Answer: C (225°)

Explanation

PQR is a right-angled isosceles triangle, so from R the line to P points 45° south of due west, a bearing of 180° + 45° = 225°.

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Question 31

Loci

The locus of a point P which moves on one side only of a straight line XY so that ∠XPY = 90° is

  1. A.a circle
  2. B.a semicircle
  3. C.an arc of a circle through X, Y
  4. D.the perpendicular bisector of XY
Show the answer and explanation

Answer: B (a semicircle)

Explanation

The angle in a semicircle is 90°, so P lies on the semicircle with XY as diameter (one side only).

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Question 32

Trigonometry

If π/2 ≤ θ ≤ 2π, find the maximum value of f(θ) = 4/(6 + 2cosθ)

  1. A.4
  2. B.1
  3. C.2/3
  4. D.1/3
Show the answer and explanation

Answer: B (1)

Explanation

The fraction is largest when the denominator is smallest, at cos θ = −1 (θ = π): f = 4/(6 − 2) = 1.

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Question 33

Mensuration of Plane Shapes

XYZ is a circle with center O and radius 7cm. Find the area of the shaded region. [π = 22/7]

Diagram for this question
  1. A.84cm2
  2. B.77cm2
  3. C.38cm2
  4. D.14cm2
Show the answer and explanation

Answer: D (14cm2)

Explanation

∠XZY = 45°, so ∠XOY = 90°. Shaded segment = sector − triangle = ¼ × 22/7 × 49 − ½ × 7 × 7 = 38.5 − 24.5 = 14cm2.

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Question 34

Coordinate Geometry

A triangle has vertices P(−1,6), Q(−3,−4) and R(1,−4). Find the midpoints of PQ and QR respectively.

  1. A.(0,−2) and (−1,−4)
  2. B.(−1,0) and (−1,−1)
  3. C.(−2,1) and (0,1)
  4. D.(−2,1) and (−1,−4)
Show the answer and explanation

Answer: D ((−2,1) and (−1,−4))

Explanation

Midpoint of PQ = ((−1 − 3)/2, (6 − 4)/2) = (−2, 1). Midpoint of QR = ((−3 + 1)/2, (−4 − 4)/2) = (−1, −4).

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Question 35

Circle Theorems

In the diagram above, PQR is a straight line and PS is a tangent to the circle QRS with |PS| = |SR| and ∠SPR = 40°. Find ∠PSQ.

Diagram for this question
  1. A.40°
  2. B.30°
  3. C.20°
  4. D.10°
Show the answer and explanation

Answer: A (40°)

Explanation

Triangle PSR is isosceles, so ∠SRP = 40°. By the alternate segment theorem ∠PSQ = ∠SRQ = 40°.

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Question 36

Differentiation

Find the slope of the curve y = 2x2 + 5x − 3 at (1,4).

  1. A.4
  2. B.6
  3. C.7
  4. D.9
Show the answer and explanation

Answer: D (9)

Explanation

dy/dx = 4x + 5, which is 9 at x = 1.

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Question 37

Integration

Evaluate ∫23 (x2 − 2x)dx

  1. A.4
  2. B.2
  3. C.4/3
  4. D.1/3
Show the answer and explanation

Answer: C (4/3)

Explanation

[x3/3 − x2] from 2 to 3 = (9 − 9) − (8/3 − 4) = 4/3.

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Question 38

Differentiation

If y = 3 sin(−4x), dy/dx is

  1. A.12x cos(4x)
  2. B.−12x cos(−4x)
  3. C.−12 cos(−4x)
  4. D.12 sin(−4x)
Show the answer and explanation

Answer: C (−12 cos(−4x))

Explanation

By the chain rule, dy/dx = 3 cos(−4x) × (−4) = −12 cos(−4x).

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Question 39

Differentiation

Determine the maximum value of y = 3x2 − x3.

  1. A.0
  2. B.2
  3. C.4
  4. D.6
Show the answer and explanation

Answer: C (4)

Explanation

dy/dx = 6x − 3x2 = 0 at x = 0 or 2; the second derivative is negative at x = 2, so the maximum is 12 − 8 = 4.

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Question 40

Measures of Central Tendency

By how much will the mean of 30, 56, 31, 55, 43 and 44 less than the median?

  1. A.0.75
  2. B.0.50
  3. C.0.33
  4. D.0.17
Show the answer and explanation

Answer: C (0.33)

Explanation

Mean = 259/6 ≈ 43.17. In order 30, 31, 43, 44, 55, 56, so the median is 43.5. Difference ≈ 0.33.

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Question 41

Measures of Dispersion

The range of 4, 3, 11, 9, 6, 15, 19, 23, 27, 24, 21 and 16 is

  1. A.16
  2. B.21
  3. C.23
  4. D.24
Show the answer and explanation

Answer: D (24)

Explanation

Range = largest − smallest = 27 − 3 = 24.

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Question 42

Measures of Central Tendency

Value: 0, 1, 2, 3, 4
Frequency: 1, 2, 2, 1, 9
Find the mean of the distribution above.

  1. A.1
  2. B.2
  3. C.3
  4. D.4
Show the answer and explanation

Answer: C (3)

Explanation

Σfx = 0 + 2 + 4 + 3 + 36 = 45 and Σf = 15, so the mean = 45/15 = 3.

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Question 43

Data Presentation

On a pie chart, there are four sectors of which three angles are 45°, 90° and 135°. If the smallest sector represents N28.00, how much is the largest sector?

  1. A.N96.00
  2. B.N84.00
  3. C.N48.00
  4. D.N42.00
Show the answer and explanation

Answer: B (N84.00)

Explanation

The fourth angle is 90°, so the largest sector is 135°, three times the smallest (45°): 3 × N28 = N84.

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Question 44

Probability

Two dice are thrown. What is the probability that the sum of the numbers is divisible by 3?

  1. A.2/3
  2. B.½
  3. C.1/3
  4. D.¼
Show the answer and explanation

Answer: C (1/3)

Explanation

Sums of 3, 6, 9 and 12 occur in 2 + 5 + 4 + 1 = 12 of the 36 outcomes, so the probability is 12/36 = 1/3.

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Question 45

Permutation and Combination

If nP3 − 6(nC4) = 0, find the value of n.

  1. A.5
  2. B.6
  3. C.7
  4. D.8
Show the answer and explanation

Answer: C (7)

Explanation

n(n − 1)(n − 2) = 6 × n(n − 1)(n − 2)(n − 3)/24, so 1 = (n − 3)/4 and n = 7.

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Question 46

Permutation and Combination

Find the number of committees of three that can be formed consisting of two men and one woman from four men and three women.

  1. A.3
  2. B.6
  3. C.18
  4. D.24
Show the answer and explanation

Answer: C (18)

Explanation

Choose 2 of 4 men (6 ways) and 1 of 3 women (3 ways): 6 × 3 = 18.

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Question 47

Measures of Dispersion

The mean of the numbers 3, 6, 4, x and 7 is 5. Find the standard deviation.

  1. A.√2
  2. B.√3
  3. C.2
  4. D.3
Show the answer and explanation

Answer: A (√2)

Explanation

3 + 6 + 4 + x + 7 = 25, so x = 5. Squared deviations are 4, 1, 1, 0, 4, total 10; variance = 10/5 = 2, so SD = √2.

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Question 48

Probability

A bag contains 5 black balls and 3 red balls. Two balls are picked randomly without replacement. What is the probability that a black and a red ball are picked?

  1. A.15/28
  2. B.13/28
  3. C.5/14
  4. D.3/14
Show the answer and explanation

Answer: A (15/28)

Explanation

P = (5/8 × 3/7) + (3/8 × 5/7) = 15/56 + 15/56 = 15/28.

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Question 49

Data Presentation

The histogram above shows the ages of the victims of a pollution. How many people were involved in the pollution?

Diagram for this question
  1. A.15
  2. B.18
  3. C.20
  4. D.21
Show the answer and explanation

Answer: C (20)

Explanation

Add the heights of the bars: 3 + 4 + 5 + 6 + 2 = 20 people.

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Question 50

Probability

Number: 1, 2, 3, 4, 5, 6
Frequency: 12, 20, x, 21, x − 1, 28
The result of tossing a fair dice 120 times is summarized above. Find the value of x.

  1. A.19
  2. B.20
  3. C.21
  4. D.22
Show the answer and explanation

Answer: B (20)

Explanation

12 + 20 + x + 21 + (x − 1) + 28 = 120, so 80 + 2x = 120 and x = 20.

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