WAEC Mathematics Past Questions & Answers - Page 323

1,611.

While doing his physics practical, Idowu recorded a reading as 1.12cm instead of 1.21cm. Calculate his percentage error

A.

1.17%

B.

6.38%

C.

7.44%

D.

8.035%

E.

9.00%

Correct answer is C

%error = \(\frac{1.21 - 1.12}{1.21} \times 100%\)

= \(\frac{9}{121} \times 100%\)

= 7.44%

1,612.

If log x = \(\bar{2}.3675\) and log y = 0.9750, what is the value of x + y? Correct to three significant figures

A.

1.18

B.

1.31

C.

9.03

D.

9.44

E.

9.46

Correct answer is E

log x = \(\bar{2}.3675\) ; log y = 0.9750

\(x = 10^{\bar{2}.3675} = 0.02331 \)

\(y = 10^{0.9750} = 9.441 \)

\(x + y = 9.4641 \approxeq 9.46\)

1,613.

Evaluate using the logarithm table, log(0.65)2

A.

1.6258

B.

0.6272

C.

0.6258

D.

3.6258

E.

1.6272

Correct answer is D

log(0.65)2 = 2log(0.65) but log0.65 = 1.8129
∴2 x 1.8129 = 3.6258

1,614.

Simplify \(\frac{\log \sqrt{8}}{\log 8}\)

A.

1/3

B.

1/2

C.

1/3log√2

D.

1/3log√8

E.

1/2log√2

Correct answer is B

\(\frac{\log \sqrt{8}}{\log 8}\)

= \(\frac{\log 8^{\frac{1}{2}}}{log 8}\)

= \(\frac{\frac{1}{2} \log 8}{\log 8}\)

= \(\frac{1}{2}\) 

1,615.

Given that 1/3log10 P = 1, find the value of P

A.

1/10

B.

3

C.

10

D.

100

E.

1000

Correct answer is E

1/3log10P = 1
log10P1/3 = log1010
P1/3 = 10 P = 1000