2017 - JAMB Mathematics Past Questions and Answers - page 1

1

Given T = { even numbers from 1 to 12 }
N = {common factors of 6, 8 and 12}
Find T ∩ N

A
{2, 3}
B
{2, 3, 4}
C
{3, 4, 6}
D
{2}
correct option: d

T = {evenn numbers from 1 to 12}

N = {common factors of 6,8 and 12}

Find T ∩ N

T = {2, 4, 6, 8, 10, 12}

N = {2}

T ∩ N = {2} i.e value common to T & N

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2
What is the next number in the series 2, 1, \(\frac{1}{2}\), \(\frac{1}{4}\)...
A
\(\frac{1}{3}\)
B
\(\frac{2}{8}\)
C
\(\frac{3}{7}\)
D
\(\frac{1}{8}\)
correct option: d

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

There are 4 terms in the series

Therefore the next number will be the 5th term

Tn = ar(^{n − 1}) (formular for geometric series)

a = first term = 2

r = common rate = (\frac{\text{next term}}{\text{previous term}}) = (\frac{1}{2})

n = number of terms

T5 = 5th term = ?

T5 = ar(^{5 - 1})

= ar(^4)

= 2 × (ar(^{n − 1}))4

= 2 × (\frac{1}{16})

= (\frac{1}{8})

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3
If U = {x : x is an integer and 1 ≤ x ≤ }
E1 = {x: x is a multiple of 3}
E2 = {x: x is a multiple of 4} and an integer is picked at random from U, find the probability that it is not in E2
A
\(\frac{3}{4}\)
B
\(\frac{3}{10}\)
C
\(\frac{1}{4}\)
D
\(\frac{1}{20}\)
correct option: a

U = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20}

E1 = {3, 6, 9, 12, 15, 18}

E2 = {4, 8, 12, 16, 20}

Probability of E2 = (\frac{5}{20}) i.e (\frac{\text{Total number in}E_2}{\text{Entire number in set}})

Probability of set E2 = 1 − (\frac{5}{20})

= (\frac{15}{20})

= (\frac{3}{4})

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4
The curved surface area of a cylinder 5cm high is 110cm2. Find the radius of its base
π = \(\frac{22}{7}\)
A
2.6cm
B
3.5cm
C
3.6cm
D
7.0cm
correct option: b

Curved surface area of cylinder = 2πrh

110 = 2 × (\frac{22}{7}) × r × 5

r = (\frac{110 \times 7}{44 \times 5})

= 3.5cm

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5
If two graphs Y = px2 + q and y = 2x2 − 1 intersect at x =2, find the value of p in terms of q
A
q − \(\frac{8}{7}\)
B
7 − \(\frac{q}{4}\)
C
8 − \(\frac{q}{2}\)
D
7 + \(\frac{q}{8}\)
correct option: b

Y = Px2 + q

Y = 2x2 - 1

Px2 + q = 2x2 - 1

Px2 = 2x2 - 1 - q

p = (\frac{2x^2 - 1 - q}{x^2})

at x = 2

P = (\frac{2(2)^2 - 1 - q}{2^2})

= (\frac{2(4) - 1 -q}{4})

= (\frac{8 - 1 - q}{4})

P = (\frac{7 - q}{4})

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6
Evaluate (\(\sin\)45o + \(\sin\)3o ) in surd form
A
\(\frac{\sqrt{3}}{2\sqrt{2}}\)
B
√3 − \(\frac{1}{2}\)
C
\(\frac{1}{2}\)√2
D
1 + \(\frac{\sqrt{2}}{2}\)
correct option: d

hypotenuse

sin = (\frac{1}{2})

(\sin45 = \frac{1}{\sqrt{2}})

= (\frac{2}{2})

∴ (sin45 + sin30)

= (\frac{1}{\sqrt{2}} + \frac{1}{2})

= (\frac{\sqrt{2}}{2}) + (\frac{1}{2})

= (\frac{\sqrt{2} + 1}{2})

= (\frac{1 + \sqrt{2}}{2})

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7
If y = x Sin x, find \(\frac{dy}{dx}\) when x = \(\frac{\pi}{2}\)
A
\(\frac{- \pi}{2}\)
B
-1
C
1
D
\(\frac{ \pi}{2}\)
correct option: c

y = xsinx

(\frac{dy}{dx}) = (1 \sin x + x \cos x)

= (\sin x + x \cos x)

At x = (\frac{\pi}{2})

= sin(\frac{\pi}{r}) + (\frac{\pi}{2} \cos {\frac{\pi}{2}})

= 1 + (\frac{\pi}{2}) × 10

= 1

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8
If temperature t is directly proportional to heat h, and when t = 20oC, h = 50 J, find t when h = 60J
A
24oC
B
20oC
C
34oC
D
30oC
correct option: a

t ∝ h, t = 20, h

t = ? h = 60

t = kh where k is constant

20 = 50k

k = (\frac{20}{50})

k = (\frac{2}{5})

when h = 60, t = ?

t = (\frac{2}{5}) × 60

t = 24oC

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9
Evaluate 1 - (\(\frac{1}{5}\) x \(\frac{2}{3}\)) + ( 5 + \(\frac{2}{3}\))
A
4
B
3
C
2\(\frac{2}{3}\)
D
3\(\frac{2}{3}\)
correct option: d
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10
Given m = N\(\frac{\sqrt{SL}}{T}\) make T the subject of the formula
A
\(\frac{\text{NSL}}{M}\)
B
\(\frac{N^2SL}{M^2}\)
C
\(\frac{N^2SL}{M}\)
D
\(\frac{NSL}{M^2}\)
correct option: b

M = (\frac{\sqrt{SL}}{T}),

make T subject of formula square both sides

M2 = (\frac{N^2SL}{T})

TM2 = N2SL

T = (\frac{N^2SL}{M^2})

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