WAEC Mathematics Past Questions & Answers - Page 267

1,331.

Expand (2x - 5)(x - 3)

A.

x2 - 1x -15

B.

2x2 - 11x + 15

C.

22 - 5x - 8

D.

x2 - 5x - 15

E.

2x2 - 6x + 15

Correct answer is B

(2x - 5)(x - 3)
2x\(^2\) - 5x - 6x + 15
2x\(^2\) - 11x + 15

1,332.

Find the 9th term of the arithmetic progression 18, 12, 6, 0, -6 .........

A.

-54

B.

-30

C.

30

D.

42

E.

66

Correct answer is B

18, 12, 6, 0, -6, 12, -18, 24, -30
9th term = -30

1,333.

A boy measured the length and breath of a rectangular lawn as 59.6m and 40.3m respectively instead of 60m and 40m. What is the percentage error in his calculation of the perimeter of the lawn?

A.

10%

B.

1.4%

C.

7%

D.

0.2%

E.

0.1%

Correct answer is E

Length = 59.6m Breath = 40.3m Perimeter = (59.6m + 40.3m) x 2 = 99.9 x 2 = 199.8m Actual measurement Perimeter = (60 + 40) x 2 = 100 x 2 = 200m Error = 200m - 199.8m = 0.2 Error =0.2/200 x 100/1 = 0.1%

1,334.

Simplufy Log104 + Log1025

A.

1

B.

2

C.

3

D.

4

E.

5

Correct answer is B

Log104 + Log1025 = Log10(4 + 25)
= Log10100 = Log10102
= 2Log1010 = 2 x 1 = 2

1,335.

Simplify 56x\(^{-4}\) \(\div\) 14x\(^{-8}\)

A.

2x-12

B.

3x-3

C.

4x-4

D.

4x-3

E.

4x4

Correct answer is E

\(56x^{-4} \div 14x^{-8}\)

= \(4x^{- 4 - (-8)}\)

= \(4x^{4}\)