JAMB Mathematics Past Questions & Answers - Page 270

1,346.

The following marks were obtained by twenty students in an examination: 53, 30, 70, 84, 59, 43, 90, 20, 78, 48, 44, 60, 81, 73, 50, 37, 67, 68, 64, 52. Find the numbers of students who scored at least 50 marks

A.

6

B.

10

C.

13

D.

14

Correct answer is D

Number of students scoring at least 50 marks = Number of students scoring 50 and above From the table 53, 70, 84, 59, 90, 60, 81, 73, 50, 37, 67, 68, 64, 52. Hence, 14 students scored at least 50 marks

1,347.

Quantities in the proportions 1, 4, 6, 7 are to be represented in a pie chart. Calculate the angle of the sector with proportion 7

A.

20o

B.

80o

C.

120o

D.

140o

Correct answer is D

Angle corresponding to 7 in a pie chart will be \(\frac{7 \times 360}{\text{sum of items}}\)

= \(\frac{7 }{18}\) x 360

= 140o

1,348.

If two angles of a triangle are 30° each and the longest side is 10cm. Calculate the length of each of the other sides.

A.

5cm

B.

4cm

C.

3√3 cm

D.

\(\frac{10\sqrt{3}}{3}\)cm

Correct answer is D

Let each of the unknown side be x.

\(10^{2} = x^{2} + x^{2} - 2(x)(x) \cos 120\)

\(100 = 2x^{2} - 2x^{2} \cos 120\)

\(100 = 2x^{2} + x^{2} = 3x^{2}\)

x = \(\sqrt{\frac{100}{3}}\)

= \(\frac{10}{\sqrt{3}}\) x \(\frac{\sqrt{3}}{\sqrt{3}}\)

x = \(\frac{10\sqrt{3}}{3}\)cm

1,349.

If sin \(\theta\) = cos \(\theta\), find \(\theta\) between 0° and 360°

A.

45o, 225o

B.

135o, 315o

C.

45o, 315o

D.

135o, 225o

Correct answer is A

sin \(\theta\) = cos \(\theta\) 0 \(\leq\) \(\theta\) \(\leq\) 360°

The acute angle where sin \(\theta\) = cos \(\theta\) = 45°

But at the third Quadrant Cos \(\theta\) = -ve; sin \(\theta\) = -ve.

at the 3rd quadrant, value with respect to Q is

(180 + Q) where Q = acute angle

(180 + 45) = 225°

The two solution are 45°, 225°

1,350.

The angle between latitudes 30oS and 13oN is

A.

17o

B.

33o

C.

43o

D.

53o

Correct answer is C

The angle between 2 latitudes one in northern hemisphere and the other in southern hemisphere and the other in southern hemisphere is the sum of their latitudes.

∴ Total angle difference = (30 + 13) = 43o