JAMB Mathematics Past Questions & Answers - Page 263

1,311.

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

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

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

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

1,312.

The locus of a point which is equidistant from two given fixed points is the

A.

perpendicular bisector of the straight line joining them

B.

parallel line to the straight line joining them

C.

transverse to the straight line joining them

D.

angle bisector of 90o which the straight line joining them makes with the horizontal

Correct answer is A

No explanation has been provided for this answer.

1,313.

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°

1,314.

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.

1,315.

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°

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

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

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