JAMB Mathematics Past Questions & Answers - Page 135

671.

PQRS is a desk of dimensions 2m x 0.8 which is inclined at 30o to the horizontal. Find the inclination of the diagonal PR to the horizontal

A.

30o 35'

B.

30o 32'

C.

15o 36'

D.

10o

E.

10o 42'

Correct answer is E

tan\(\theta\) = \(\frac{0.8}{2}\) = (0.4)

\(\theta\) = tan-1(0.4)

From the diagram, the inclination of the diagonal PR to the horizontal is 10o 42'

672.

The figure FGHK is a rhombus. What is the value of angle X?

A.

30o

B.

90o

C.

150o

D.

120o

E.

60o

Correct answer is D

< HKF = 60o, < KFG = 120o

< KFG = < KHG = x(opposite angles)

x = 120o

673.

Which of the following equations represents the graph?

A.

y = 1 + 2x + 3x2

B.

y = 1 - 2x + 3x2

C.

y = 1 + 2x - 3x2

D.

y = 1 - 2x - 3x2

E.

y = 3x2 + 2x - 1

Correct answer is E

The roots of the function are 1 and \(\frac{1}{3}\)

sum of roots = -1 + \(\frac{1}{3}\) = -\(\frac{2}{3}\)

product of roots = -1 x \(\frac{1}{3}\) = -\(\frac{1}{3}\)

x2 - (sum of roots)x + (product of roots) = 0

x2 + (-\(\frac{2}{3}\))x - (-\(\frac{1}{3}\)) = 0

x2 + \(\frac{2x}{3}\) - \(\frac{1}{3}\) = 0

3x2 + 2x - 1 = 0

674.

In the figure, find PRQ

A.

66\(\frac{1}{2}\)o

B.

62\(\frac{1}{2}\)o

C.

125o

D.

105o

E.

65o

Correct answer is B

Angle subtended at any part of the circumference of the circle \(\frac{125^o}{2}\) at centre = 360o - 235o = 125o

\(\bar{PQR}\) = \(\frac{125}{2}\)

= 62\(\frac{1}{2}\)o

675.

In a class of 60 pupils, the statistical distribution of the numbers of pupils offering Biology, History, French, Geography and Additional mathematics is as shown in the pie chart. How many pupils offer Additional Mathematics?

A.

15

B.

10

C.

18

D.

12

E.

20

Correct answer is B

(2x - 24)° + (3x - 18)° + (2x + 12)° + (x + 12)° + x° = 360°

9x = 360° + 18°

x = \(\frac{378}{9}\)

= 42°, if x = 42°, then add maths = \(\frac{2x - 42}{360}\) x 60

= \(\frac{2 \times 42 - 24}{360}\) x 60

= \(\frac{84 - 24}{6}\)