Year : 
2018
Title : 
Mathematics (Core)
Exam : 
JAMB Exam

Paper 1 | Objectives

51 - 60 of 62 Questions

# Question Ans
51.

Out of 7 consonants and 4 vowels, how many words of 3 consonants and 2 vowels can be formed?

A. 210

B. 1050

C. 21400

D. 25200

Detailed Solution

To form words having 3 consonants and 2 vowels out of 7 consonants and 4 vowels, the number of such words is 7/3C x 4/2C = 35 x 6
= 210
There is an explanation video available below.
52.

From a point P, Q is 5km due West and R is12km due South of Q. Find the distance between P and R.

A. 5km

B. 12km

C. 13km

D. 17km

Detailed Solution

Using Pythagoras theorem
PR\(^2\) = 5\(^2\) + 12\(^2\)
25 + 144 = 169
PR = √(169)= 13km

There is an explanation video available below.
53.

If y = 23\(_{five}\) + 101\(_{three}\) find y leaving your answer in base two

A. 1110

B. 10111

C. 11101

D. 111100

Detailed Solution

First we convert the numbers to base ten
23\(_{five}\)= 2 x 51 + 3 x 50
= 10 + 3 = 13
101\(_{five}\) = (1 x 32) + (0 x 31) + (1 x 30)
= 9 + 0 + 1 = 10
So, y = 13 + 10 = 23
To convert 23 to base 2 (as in the diagram above)
Y = 23
= 10111\(_{five}\)
Answer is B
There is an explanation video available below.
54.

A box contains two red balls and four blue balls. A ball is drawn at random from the box and then replaced before a second ball is drawn. Find the probability of drawing two red balls.

A. \(\frac{2}{3}\)

B. \(\frac{1}{3}\)

C. \(\frac{1}{4}\)

D. \(\frac{1}{9}\)

Detailed Solution

Total number of balls = 2 + 4 = 6
P(of picking a red ball) = \(\frac{2}{6}\) = \(\frac{1}{3}\)
P(of picking a blue ball) = \(\frac{4}{6}\) = \(\frac{2}{3}\)
With replacement,
P( picking two red balls) = \(\frac{1}{3}\) × \(\frac{1}{3}\) = \(\frac{1}{9}\)
There is an explanation video available below.
55.

Which one of the following gives the members of the set A1 n B n C?

A. Φ

B. {s}

C. {t, u}

D. {y, z}

Detailed Solution

A1 = Elements in the universal set but not in A = {s, w, x, y, z}
B = {r, s. t, u}
C = {t, u, v, w, x}
A1 n B n C = elements common to the three sets = none = empty set = Φ
There is an explanation video available below.
56.

Calculate the area of an equilateral triangle of side 8cm

A. 8√3

B. 16

C. 4√3

D. 16√3

Detailed Solution

An equilateral triangle has all sides equal and all angles equal as 600
Area = \(\frac{1}{2}\) absinθ
Area = \(\frac{1}{2}\) x 8 x 8 x sin60
= \(\frac{1}{2}\) x 64 x \(\sqrt{\frac{3}{2}}\)
= 16√3 cm\(^2\)
There is an explanation video available below.
57.

Approximate 0.9875 to 1 decimal place.

A. 1.1

B. 1.0

C. 0.9

D. 0.10

Detailed Solution

9 is on one decimal place, the next number to it is 8 which will be rounded up to 1 because it is greater than 5 and then added to 9 to give 10, 10 cannot be written, it will then be rounded up to 1 and added to 0.
So the answer is 1.0
There is an explanation video available below.
58.

Simplify 25\(\frac{1}{2}\) × 8\(\frac{-2}{3}\)

A. 1\(\frac{1}{4}\)

B. 2\(\frac{1}{4}\)

C. 6

D. 10

Detailed Solution

Using law of indices
25\(\frac{1}{2}\) × 8\(\frac{-2}{3}\)
= √25 x (\(\sqrt[3]{8}\)) -2
= 5 x 2-2
= 5 x \(\frac{1}{2^2}\) =
\(\frac{5}{4}\) = \(\frac{11}{4}\)
Answer is A
There is an explanation video available below.
59.

From a point R, 300m north of P, a man walks eastwards to a place; Q which is 600m from P. Find the bearing of P from Q correct to the nearest degree

A. 026\(^o\)

B. 045\(^o\)

C. 210\(^o\)

D. 240\(^o\)

Detailed Solution

Cos θ = \(\frac{adj}{hyp}\)
= \(\frac{300}{600}\)
= 0.5
θ = Cos - 10.5
= 60
∠ RPQ = ∠ PQs
So the bearing of P from Q is 180 + 60 = 240\(^o\)
Answer is D
There is an explanation video available below.
60.

Add 54 \(_{eight}\) and 67\(_{eight}\) giving your answers in base eight

A. 111

B. 121

C. 123

D. 143

Detailed Solution

54 \(_{eight}\) and 67\(_{eight}\) = 1438
Starting with normal addition, 4 + 7 gives 11
(it is more than the base, 8) 8 goes in 11 just 1 time, remaining 3, the remainder will be written, and the 1 will be added to the sum of 5 and 6 which gives 12 altogether, 8 goes in 12 one time remaining 4, the remainder 4 was written and then the 1 that was the quotient was then written since nothing to add the 1 to.
So answer is 143 in base eight
There is an explanation video available below.
51.

Out of 7 consonants and 4 vowels, how many words of 3 consonants and 2 vowels can be formed?

A. 210

B. 1050

C. 21400

D. 25200

Detailed Solution

To form words having 3 consonants and 2 vowels out of 7 consonants and 4 vowels, the number of such words is 7/3C x 4/2C = 35 x 6
= 210
There is an explanation video available below.
52.

From a point P, Q is 5km due West and R is12km due South of Q. Find the distance between P and R.

A. 5km

B. 12km

C. 13km

D. 17km

Detailed Solution

Using Pythagoras theorem
PR\(^2\) = 5\(^2\) + 12\(^2\)
25 + 144 = 169
PR = √(169)= 13km

There is an explanation video available below.
53.

If y = 23\(_{five}\) + 101\(_{three}\) find y leaving your answer in base two

A. 1110

B. 10111

C. 11101

D. 111100

Detailed Solution

First we convert the numbers to base ten
23\(_{five}\)= 2 x 51 + 3 x 50
= 10 + 3 = 13
101\(_{five}\) = (1 x 32) + (0 x 31) + (1 x 30)
= 9 + 0 + 1 = 10
So, y = 13 + 10 = 23
To convert 23 to base 2 (as in the diagram above)
Y = 23
= 10111\(_{five}\)
Answer is B
There is an explanation video available below.
54.

A box contains two red balls and four blue balls. A ball is drawn at random from the box and then replaced before a second ball is drawn. Find the probability of drawing two red balls.

A. \(\frac{2}{3}\)

B. \(\frac{1}{3}\)

C. \(\frac{1}{4}\)

D. \(\frac{1}{9}\)

Detailed Solution

Total number of balls = 2 + 4 = 6
P(of picking a red ball) = \(\frac{2}{6}\) = \(\frac{1}{3}\)
P(of picking a blue ball) = \(\frac{4}{6}\) = \(\frac{2}{3}\)
With replacement,
P( picking two red balls) = \(\frac{1}{3}\) × \(\frac{1}{3}\) = \(\frac{1}{9}\)
There is an explanation video available below.
55.

Which one of the following gives the members of the set A1 n B n C?

A. Φ

B. {s}

C. {t, u}

D. {y, z}

Detailed Solution

A1 = Elements in the universal set but not in A = {s, w, x, y, z}
B = {r, s. t, u}
C = {t, u, v, w, x}
A1 n B n C = elements common to the three sets = none = empty set = Φ
There is an explanation video available below.
56.

Calculate the area of an equilateral triangle of side 8cm

A. 8√3

B. 16

C. 4√3

D. 16√3

Detailed Solution

An equilateral triangle has all sides equal and all angles equal as 600
Area = \(\frac{1}{2}\) absinθ
Area = \(\frac{1}{2}\) x 8 x 8 x sin60
= \(\frac{1}{2}\) x 64 x \(\sqrt{\frac{3}{2}}\)
= 16√3 cm\(^2\)
There is an explanation video available below.
57.

Approximate 0.9875 to 1 decimal place.

A. 1.1

B. 1.0

C. 0.9

D. 0.10

Detailed Solution

9 is on one decimal place, the next number to it is 8 which will be rounded up to 1 because it is greater than 5 and then added to 9 to give 10, 10 cannot be written, it will then be rounded up to 1 and added to 0.
So the answer is 1.0
There is an explanation video available below.
58.

Simplify 25\(\frac{1}{2}\) × 8\(\frac{-2}{3}\)

A. 1\(\frac{1}{4}\)

B. 2\(\frac{1}{4}\)

C. 6

D. 10

Detailed Solution

Using law of indices
25\(\frac{1}{2}\) × 8\(\frac{-2}{3}\)
= √25 x (\(\sqrt[3]{8}\)) -2
= 5 x 2-2
= 5 x \(\frac{1}{2^2}\) =
\(\frac{5}{4}\) = \(\frac{11}{4}\)
Answer is A
There is an explanation video available below.
59.

From a point R, 300m north of P, a man walks eastwards to a place; Q which is 600m from P. Find the bearing of P from Q correct to the nearest degree

A. 026\(^o\)

B. 045\(^o\)

C. 210\(^o\)

D. 240\(^o\)

Detailed Solution

Cos θ = \(\frac{adj}{hyp}\)
= \(\frac{300}{600}\)
= 0.5
θ = Cos - 10.5
= 60
∠ RPQ = ∠ PQs
So the bearing of P from Q is 180 + 60 = 240\(^o\)
Answer is D
There is an explanation video available below.
60.

Add 54 \(_{eight}\) and 67\(_{eight}\) giving your answers in base eight

A. 111

B. 121

C. 123

D. 143

Detailed Solution

54 \(_{eight}\) and 67\(_{eight}\) = 1438
Starting with normal addition, 4 + 7 gives 11
(it is more than the base, 8) 8 goes in 11 just 1 time, remaining 3, the remainder will be written, and the 1 will be added to the sum of 5 and 6 which gives 12 altogether, 8 goes in 12 one time remaining 4, the remainder 4 was written and then the 1 that was the quotient was then written since nothing to add the 1 to.
So answer is 143 in base eight
There is an explanation video available below.