JAMB Mathematics Past Questions & Answers - Page 121

601.

PQRST is a regular pentagon and PQVU is a rectangle with U and V lying on TS and SR respectively as shown in the diagram. Calculate TUP

A.

18o

B.

54o

C.

90o

D.

108o

Correct answer is B

The total angle in a regular pentagon = \((2(5) - 4) \times 90\)

= \(6 \times 90 = 540°\)

Each interior angle = \(\frac{540}{5} = 108°\)

While the interior of a quadrilateral = \(\frac{360}{4} = 90°\)

\(PTU + TPU + TUP = 180°\)

\(108° + (180° - 90°) + TUP = 180°\)

\(TUP = 180° - (108° + 18°) = 54°\)

602.

The figure represents the graphs of y = x(2 - x) and y = (x - 1)(x - 3). What are the x-coordinates of P, Q and F respectively?

A.

1, 3, 2

B.

0, 0, 0

C.

0, 2, 3

D.

1, 2, 3

Correct answer is D

The two equations are y = x(2 - x) and y = (x - 1)(x - 3)

The root of these equations are points where the graph of the equations cuts the x axis; but at these points = 0

put y = 0; 0 = x(2 - x)

0 = (x - 1)(x - 3)

x = 0 or x = 2; x = 1 or x = 3

The values of x at P, Q, R are increasing towards the positive direction of x-axis

at P, x = 1 at Q, x = 2 at R, x = 3

P, Q, R are respectively (1, 2, 3)

603.

The shaded portion in the venn diagram is

A.

x \(\cap\) z

B.

xo \(\cap\) y \(\cap\) z

C.

x \(\cap\) yo \(\cap\) z

D.

x \(\cap\) y \(\cap\) zo

Correct answer is C

The shaded part exists on x \(\cap\) z but not in y

604.

In the figure, if XZ is 10cm, calculate RY in cm

A.

10

B.

10(1 - \(\frac{1}{\sqrt{3}}\))

C.

10(1 - \(\frac{1}{\sqrt{2}}\))

D.

10[1 - \(\sqrt{3}\)]

Correct answer is B

RY = YZ - RZ

= 10 tan 45 - 10 tan 30

= 10(1 - \(\frac{1}{\sqrt{3}}\))

605.

The diagram is a circle with centre O. Find the area of the shaded portion

A.

9(\(\pi - 2) cm^2\)

B.

18\(\pi cm^2\)

C.

9\(\pi cm^2\)

D.

36\(\pi cm^2\)

Correct answer is A

Area of the quadrant = \(\frac{1}{4} \pi r^2 = \frac{1}{4} \pi (6)^2\)

= \(\frac{36 \pi}{4} = 9 \pi \)

Area of the triangle = \(\frac{1}{2} \times 6 = 18 \times \sin 90^o = 18\)

Area of shaded portion =(9 \(\pi \) - 18)cm^2\) =

9(\(\pi - 2)cm^2\).