## Mathematics 2018 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.

**41. **

The table below shows the frequency of children of age x years in a hospital:

x | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |

f | 3 | 4 | 5 | 6 | 7 | 6 | 5 | 4 |

Use the table to answer the question below:

How many children are in the hospital

**A.**36**B.**40**C.**44**D.**50

**Correct Option: Answer is B**

The total number of students is ∑ f = 3 + 4 + 5 + 6 + 7 + 6 + 5 + 4

= 40

**42.**

The figure below is a Venn diagram showing the elements arranged within sets A,B,C,ε.

Use the figure to answer this question

What is n(A U B)1 ?

**A.**2**B.**3**C.**4**D.**7

**Correct Option: Answer is C**

A = (p, q, r, t, u, v)

B = (r, s, t, u)

A U B = Elements in both A and B = (p, q, r, s, t, u, v)

(A U B)1 = elements in the universal set E but not in (A U B)= (w, x, y, z)

n(A U B) 1 = number of the elements in (A U B)1 = 4

**43. **What is the loci of a distance 4cm from a given point P?

**A.**A straight line of length 4cm**B.**a circle of radius 4cm**C.**perpendicular to point P at 4cm**D.**a circle of diameter 4cm

**Correct Option: Answer is B**

Locus is the path traced at by a point which moves in accordance with a certain law. It is also the set of all possible position occupied by an object The path traced from all possible location of 4cm from a given point P form a circle of radius 4cm with centre P

**44**. Given that Sin (5\(_x\) − 28)\(^o\) = Cos(3\(_x\) − 50)\(^o\), O\(_x\) < 90\(^o\)

Find the value of x

**A.**14\(^o\)**B.**21\(^o\)**C.**32\(^o\)**D.**39\(^o\)

**Correct Option: Answer is B**

Sin(5x – 28) = Cos(3x – 50)………..i

But Sinα = Cos(90 – α)

So Sin(5x – 28) = Cos(90 – [5x – 28])

Sin(5x – 28) = Cos(90 – 5x + 28)

Sin(5x – 28) = Cos(118 – 5x)………ii

Combining i and ii

Cos(3x – 50) = Cos(118 – 5x)

3x – 50 = 118 – 5x

Collecting the like terms

3x + 5x = 118 + 50

8x = 168

x = \(\frac{168}{8}\)

x = 21\(^o\)

**45**. Find the average of the first four prime numbers greater than 10

**A.**20**B.**19**C.**17**D.**15

**Correct Option: Answer is D**

Prime numbers are numbers that has only two factors (i.e 1 and itself). They are numbers that are only divisible by 1 and their selves. First four Prime numbers greater than 10 are 11, 13, 17 and 19

Average = sum of numbers / number

= (11+13+17+19)/4

= 604

= 15

**46. **Find the average of the first four prime numbers greater than 10

**A.**20**B.**19**C.**17**D.**15

**Correct Option: Answer is B**

**47. **Convert 0.04945 to two significant figures

**A.**0.040**B.**0.049**C.**0.050**D.**0.49

**Correct Option: Answer is B**

**48. **Calculate 243\(_{six}\) – 243\(_{five}\) expressing your answer in base 10

**A.**0**B.**1**C.**26**D.**46

**Correct Option: Answer is C**

Since they are of different base, convert to base 10

243\(_{six}\) = (2 x 62) + (4 x 61) + (3 x 60)

= 72 + 24 + 3 = 99 base 10

243\(_{six}\) = 2 x 52 + 4 x 51 +3 x 50

50 + 20 + 3 = 73 base 10

Subtracting them, 99 – 73

= 26

**49. **Evaluate ∫\(^2_1\) \(\frac{5}{x}\) dx

**A.**1.47**B.**2.67**C.**3.23**D.**3.47

**Correct Option: Answer is C**

∫\(\frac{5}{x}\) dx = 5 ∫\(\frac{1}{x}\) = 5Inx

Since the integral of \(\frac{1}{x}\) is Inx

∫\(^2\) \(_1\)∫ \(\frac{5}{x}\) dx = 5

dx = 5 (In<2 – InIn1)

= 3.4657

= 3.47

**50. **Tossing a coin and rolling a die are two separate events. What is the probability of obtaining a tail on the coin and an even number on the die?

**A.**1/16**B.**1/6**C.**$\frac{\mathrm{1/}}{4}$**D.**3/8