JAMB Mathematics Past Questions & Answers - Page 129

641.

In the figure, PQR is a semicircle. Calculate the area of the shaded region

A.

125\(\frac{2}{7}\)2

B.

149\(\frac{2}{7}\)cm2

C.

234\(\frac{1}{7}\)cm2

D.

267\(\frac{1}{2}\)cm2

Correct answer is A

No explanation has been provided for this answer.

642.

In the figure, YXZ = 30o, XYZ = 105o and XY = 8cm. Calculate YZ

A.

16\(\sqrt{2}\)cm

B.

8\(\sqrt{2}\)cm

C.

4\(\sqrt{2}\)cm

D.

22cm

Correct answer is C

yzx + 105o + 30o = 180o

yzx = 180 - 155 = 45o

\(\frac{yz}{sin 30^o} = \frac{8}{sin 45^o}\)

yz = \(\frac{8 \sin 30}{sin 45}\)

= 8(\(\frac{1}{2}) = \frac{8}{1} \times \frac{1}{2} \times \frac{\sqrt{2}}{1}\)

= 4 \(\div\) \(\frac{1}{\sqrt{2}}\)

= 4\(\sqrt{2}\)cm

643.

In triangles XYZ and XQP, XP = 4cm, XQ = 5cm and PQ = QY = 3cm. Find ZY

A.

8cm

B.

6cm

C.

4cm

D.

3cm

Correct answer is B

No explanation has been provided for this answer.

644.

In the figure, PS = QS = RS and QSR - 100o, find QPR

A.

40o

B.

50o

C.

80o

D.

100o

Correct answer is B

Since PS = QS = RS

S is the centre of circle passing through P, Q, R /PS/ = /RS/ = radius

QPR \(\pm\) \(\frac{100^o}{2}\) = 50o

645.

In a class of 30 students, the marks scored in an examination are displayed in the histogram. What percentage of the student scored more than 40%?

A.

14%

B.

40%

C.

46\(\frac{3}{4}\)%

D.

53\(\frac{1}{3}\)%

Correct answer is C

This histogram is transferred into this frequency table
\(\begin{array}{c|c} Marks & 20 & 40 & 60 & 80 & 100 \\ \hline students & 9 & 7 & 6 & 6 & 2\end{array}\)

Students who scored more than 40 = 6 + 6 + 2 = 14

i.e. \(\frac{14}{30}\) x 100% = 46\(\frac{3}{4}\)%