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WAEC Mathematics Past Questions & Answers - Page 292

1,456.

A sector of a circle of radius 9cm subtends angle 120° at the centre of the circle. Find the area of the sector to the nearest cm2 [Take π = 22/7]

A.

75cm2

B.

84cm2

C.

85cm2

D.

86cm2

E.

95cm2

Correct answer is C

No explanation has been provided for this answer.

1,457.

Solve the simultaneous equations y = 3x; 4y - 5x =14

A.

-2,-6

B.

2,6

C.

2,-6

D.

-2,6

E.

-1,-3

Correct answer is B

y = 3x  ... (i);

4y - 5x =14  ... (ii)

Put 3x for y in (ii).

4(3x) - 5x = 14

12x - 5x = 14

7x = 14 ⟹⟹ x = 2.

y = 3x = 3(2) = 6

(x, y) = (2, 6)

1,458.

Factorize 2x2 - 21x + 45

A.

(2x - 9)(x - 5)

B.

(2x-15)(x + 3)

C.

(2x +15)(x - 3)

D.

(2x -15(x - 3)

E.

(2x - 9)(x + 5)

Correct answer is D

2x2 - 21x + 45

= 2x2 - 15x - 6x + 45

= x(2x - 15) - 3(2x - 15)

= (x - 3)(2x - 15)

1,459.

Write as a single fraction: 56r34r

A.

r/12

B.

12/r

C.

1/6r

D.

r/6

E.

1/12r

Correct answer is E

56r34r

= 10912r

= 112r

1,460.

Solve the equation x2 - 2x - 3 = 0

A.

(-3, 1)

B.

(-1, -3)

C.

(3,1)

D.

(43, 0)

E.

(-1, 3).

Correct answer is E

x2 - 2x - 3 = 0

x2 - 3x + x - 3 = 0

x(x - 3) + 1(x - 3) = 0

(x + 1)(x - 3) = 0

x = (-1, 3)