JAMB Mathematics Past Questions & Answers - Page 258

1,286.

What is the perpendicular distance of a point (2, 3) from the line 2x - 4y + 3 = 0?

A.

\(\frac{\sqrt{5}}{2}\)

B.

\(\frac{\sqrt{5}}{20}\)

C.

\(\frac{5}{\sqrt{13}}\)

D.

6

Correct answer is A

2x - 4y + 3 = 0

Required distance = \(\frac{(2 \times 2) + 3(-4) + 3}{\sqrt{2^2} + (-4)^2}\)

= \(\frac{4 - 12 + 3}{\sqrt{20}}\)

= \(\frac{-5}{-2\sqrt{5}}\)

= \(\frac{\sqrt{5}}{2}\)

1,287.

X is a point due east of point Y on a coast: Z is another point on the coast but 6√3km due south of y.

If the distance XZ is 12Km. Calculate the bearing of Z from X

A.

240o

B.

210o

C.

150o

D.

60o

Correct answer is B

Using sinØ = \(\frac{6√3}{12}\) →  \(\frac{√3}{2}\)

sinØ = \(\frac{√3}{2}\) or 60°

The bearing of  Z from X = [270 - 60]° → 210°

1,288.

If in the diagram, FG is parallel to KM, find the value of x

A.

75o

B.

95o

C.

105o

D.

125o

Correct answer is B

No explanation has been provided for this answer.

1,289.

Determine the distance on the earth's surface between two town P (lat 60°N, Long 20°E) and Q(Lat 60°N, Long 25°W) (Radius of the earth = 6400km)

A.

\(\frac{800\pi}{9}\)km

B.

\(\frac{800\sqrt{3\pi}}{9}\)km

C.

800\(\pi\) km

D.

800\(\sqrt{3\pi}\) km

Correct answer is C

Angular difference (\(\theta\))= 25° + 20° = 45°

\(\alpha\) = common latitude = 60°

\(S = \frac{\theta}{360°} \times 2\pi R \cos \alpha\)

\(S = \frac{45°}{360°} \times 2 \pi \times 6400 \times \cos 60°\)

= \(\frac{6400\pi}{8} = 800\pi km\)

1,290.

If the angles of quadrilateral are (p + 10)°, (2p - 30)°, (3p + 20)° and 4p°, find p.

A.

63

B.

40

C.

36

D.

28

Correct answer is C

The sum of angles in a quadrilateral = 360°

\(\therefore (p + 10) + (2p - 30) + (3p + 20) + 4p = 360\)

\(10p = 360° \implies p = \frac{360}{10} = 36°\)