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JAMB Mathematics Past Questions & Answers - Page 313

1,561.

Find the equation of a line perpendicular to line 2y = 5x + 4 which passes through (4, 2).

A.

5y - 2x -18 = 0

B.

5y + 2x - 18 = 0

C.

5y - 2x + 18 = 0

D.

5y + 2x - 2 = 0

Correct answer is B

2y = 5x + 4 (4, 2)

y = 5x2 + 4 comparing with

y = mx + e

m = 52

Since they are perpendicular

m1m2 = -1

m2 = 1m1 = -1

52 = -1 x 25

The equator of the line is thus

y = mn + c (4, 2)

2 = -25(4) + c

21 + 85 = c

c = 185


y = -25x + 185

5y = -2x + 18

or 5y + 2x - 18 = 0

1,562.

The midpoint of P(x, y) and Q(8, 6) is (5, 8). Find x and y.

A.

(2, 10)

B.

(2, 8)

C.

(2, 12)

D.

(2, 6)

Correct answer is A

P(x, y) Q(8, 6)

midpoint = (5, 8)

x + 8 = 5

y+62 = 8

x + 8 = 10

x = 10 - 8 = 2

y + 6 = 16

y + 16 - 6 = 10

therefore, P(2, 10)

1,563.

The perpendicular bisector of a line XY is the locus of a point 

A.

whose distance from X is always twice its distance from Y

B.

whose distance from Y is always twice its distance from X.

C.

which moves on the line XY

D.

which is equidistant from the points X and Y

Correct answer is D

No explanation has been provided for this answer.

1,564.

A solid metal cube of side 3 cm is placed in a rectangular tank of dimension 3, 4 and 5 cm. What volume of water can the tank now hold

A.

48 cm3

B.

33 cm3

C.

60 cm3

D.

27 cm3

Correct answer is B

Volume of cube = L3

33 = 27cm3

volume of rectangular tank = L x B X h

= 3 x 4 x 5

= 60cm3

volume of H2O the tank can now hold

= volume of rectangular tank - volume of cube

= 60 - 27

= 33cm3

1,565.

A chord of circle of radius 7cm is 5cm from the centre of the circle.What is the length of the chord?

A.

4√6 cm

B.

3√6 cm

C.

6√6 cm

D.

2√6 cm

Correct answer is A

From Pythagoras theorem

|OA|2 = |AN|2 + |ON|2

72 = |AN|2 + (5)2

49 = |AN|2 + 25

|AN|2 = 49 - 25 = 24

|AN| = 24

= 4×6

= 2√6 cm

|AN| = |NB| (A line drawn from the centre of a circle to a chord, divides the chord into two equal parts)

|AN| + |NB| = |AB|

2√6 + 2√6 = |AB|

|AB| = 4√6 cm