2010 - JAMB Mathematics Past Questions and Answers - page 5

41
If \(\left[\begin{array}{cc}
x & 3\\ 2 & 7\end{array}\right]\)= 15 find the value of x
A
3
B
4
C
5
D
2
correct option: a

(\left[\begin{array}{cc}

x & 3\

2 & 7\end{array}\right])= 15
x x 7 - 2 x 3 = 15

7x - 6 = 15

7x = 15+6

7x = 21
x = 21/7
x = 3

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42
From the diagram above, find x
A
65o
B
50o
C
75o
D
55o
correct option: a

∠RTS = 90o (∠ in semi circle)

∠UTS = 25o (∠ in alternate segment)
X + 90 + 25 = 180(sum of ∠s on a str line)
X + 115 = 180
X = 180 - 115
X = 65o

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43
From the cyclic quadrilateral TUVW above, find the value of x
A
26o
B
24o
C
20o
D
23o
correct option: b

TUVW is a cyclic quad

3χ + 20 + 88 = 180 (opp ∠ s of a cyclic quad are supplementary)

3χ + 108 = 180

3χ = 180 - 108

3χ = 72
χ = 72/3
χ = 24o

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44
If two smaller sides of a right angled triangle are 4cm and 5cm, find its area
A
10 cm2
B
6 cm2
C
24 cm2
D
8 cm2
correct option: a

Area of a triangle = 1/2 base x height

= 1/2 x 4 x 5

= 10 cm2

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45
An arc subtends an angle of 50o at the center of circle of radius 6cm. Calculate the area of the sector formed
A
100/7
B
80/7
C
110/7
D
90/7
correct option: c
Area of a sector = θ x πr2
360

= 50/360 x 22/7 x 36/1

= 110/7

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46
What is the locus of point that is equidistant from points P(1,3) and Q(3,5)?
A
y = -χ + 6
B
y = -χ - 6
C
y = χ + 6
D
y = χ - 6
correct option: a

Locus of a point equidistant from two fixed points is the perpendicular bisector of the straight line joining the points Gradients of PQ = (5-3 / 3-1) = 2/2 = 1

Gradient bisector = -1

Equation of perpendicular bisector
y - y1 = m(χ - χ1
y - 4 = -χ + 2
y = + 6

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47
If the area of ΔPQR above is 12√3 cm2, find the value of q?
A
6 cm
B
7 cm
C
8 cm
D
5 cm
correct option: a

Area of a triangle = 1/2 ab Sinθ

12√3 = 1/2 x 8 x q sin 60

12√3 = 4 x q x √3/2

12√3 = 2q√3

q =12√3
2√3

q = 6

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48
If y = (2x + 1)3 find dy/dx
A
3(2x+1)2
B
6(2x+1)
C
3(2x+1)
D
6(2x+1)2
correct option: d

y = (2x + 1)3

dy/dx = 3(2x + 1)3-1 x 2

= 3(2x + 1)2 x 2

= 6(2x + 1)2

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49
Find ∫(sin x + 2)dx
A
cos x + x2 + K
B
cos x 2x + K
C
-cos x + x2 + K
D
-cos x + 2x + K
correct option: d

∫(sin χ + 2)dχ = (∫sin χ + ∫2)dx

= -cos χ + 2χ + K

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50
Marks2345678
No. of students3152423

from the table above, if the pass mark is 5, how many students failed the test?
A
6
B
2
C
7
D
9
correct option: d
MarksNumber of students
23
31
45
Total9
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