WAEC Mathematics Past Questions & Answers - Page 320

1,596.

A sector of a circle of radius 7cm has an area of 44cm2. Calculate the angle of the sector correct to the nearest degree [Take π = 22/7]

A.

6o

B.

26o

C.

52o

D.

103o

E.

206o

Correct answer is D

πr2 = 360o

44cm2 = θ; ∴ θ =
44/πr2
x 360o = 102.9o = 103o

1,597.

Solve the equation 2a\(^2\) - 3a - 27 = 0

A.

3/2, 9

B.

-2/3, 9

C.

3, 9/2

D.

-3, -9/2

E.

-3, 9/2

Correct answer is E

2a\(^2\) - 3a - 27 = 0

2a\(^2\) - 9a + 6a - 27 = 0

a(2a - 9) + 3(2a - 9) = 0

(a + 3)(2a - 9) = 0

a = -3 or a = \(\frac{9}{2}\)

1,598.

Find the value of m which makes x\(^2\) + 8 + m a perfect square

A.

2

B.

4

C.

8

D.

12

E.

16

Correct answer is E

x\(^2\) + 8 + m

To make it a perfect square, we add \((\frac{b}{2})^2\)

= \((\frac{8}{2})^2\)

= 16

1,599.

Solve the equation 7y\(^2\) = 3y

A.

y = 3 or 7

B.

y = 0 or 7

C.

y = 0 or 3/7

D.

y = 0 or 9

E.

y = 0 or 10

Correct answer is C

7y\(^2\) = 3y

7y\(^2\) - 3y = 0

y(7y - 3) = 0

y = 0 or y = \(\frac{3}{7}\)

1,600.

Factorize 2e\(^2\) - 3e + 1

A.

(2e-1) (e-1)

B.

(e+1) (2e+1)

C.

(2e+3) (e+2)

D.

(2e-3) (e-1)

E.

(e2-3(2e-1)

Correct answer is A

2e\(^2\) - 3e + 1

2e\(^2\) - 2e - e + 1

2e(e - 1) - 1(e - 1)

(2e - 1)(e - 1)