WAEC Mathematics Past Questions & Answers - Page 277

1,381.

Given that log2a = log84, find a

A.

21/3

B.

42/3

C.

42/3

D.

22/3

E.

23

Correct answer is D

Log2a = Log84
Log2a = Log882/3 → 2/3Log88 → 2/3 x 1
Log2a = 2/3
Recall; If Logax = y ∴ ay = x
Log2a = 2/3
22/3 = a

1,382.

Express 0.000834 in standard form

A.

8.34 x 10-4

B.

8.34 x 10-3

C.

8.34 x 103

D.

8.34 x 104

E.

8.34 x 106

Correct answer is A

No explanation has been provided for this answer.

1,383.

If three children shares N10.50 among themselves in ratio 6:7:8, how much is the largest share?

A.

N3.00

B.

N3.50

C.

N4.00

D.

N4.50

E.

N5.00

Correct answer is C

Ratio = 6 + 7 + 8 = 21
21 = N10.50
1 = 1050K/21 = 50K
6 = 6 x 50K = N3.00
7 = 7 x 50K = N3.50
8 = 8 x 50K = N4.00
the Largest share = N4.00

1,384.

Find (101\(_2\))\(^2\), expressing the answer in base 2.

A.

10101

B.

11001

C.

10010

D.

11101

E.

10110

Correct answer is B

You can convert it to base 10 and square, then re-convert it after the operation. 

OR

You can multiply it straight applying the rules of binary multiplication.

1,385.

The length of an exercise book is given as 20cm correct to the nearest centimeter. In which of the following ranges of possible measurement does the actual length lie?

A.

19.5 - 20.4cm

B.

19.1 - 20.9cm

C.

19.9 - 20.1cm

D.

19.95 - 20.05cm

E.

19 - 21cm

Correct answer is A

In mathematics, numbers ranging from 0.5 - 0.9 are approximated to 1, while 0.1 - 0.4 are taken down to 0.