WAEC Past Questions and Answers - Page 2395

11,971.

Simplify: \(\log_{10}\) 6 - 3 log\(_{10}\)  3 + \(\frac{2}{3} \log_{10} 27\)

A.

3 \(\log_{10}^2\)

B.

\(\log_{10}^2\)

C.

\(\log_{10}^3\)

D.

2 \(\log_{10}^3\)

Correct answer is B

log\(_{10}\) 6 - log\(_{10}\)3\(^3\) + log\(_{10}\) (\(\sqrt[3]{27}\))\(^2\)

= log \(_{10}\) 6 - log \(_{10}\) 27 + log\(_{10}\) 9

= log\(_{10}\) \(\frac{6  \times 9}{27}\)

= log\(_{10}\)2

11,972.

Solve 4x^{2}\) - 16x + 15 = 0.

A.

x = 1\(\frac{1}{2}\) or x = -2\(\frac{1}{2}\)

B.

x = 1\(\frac{1}{2}\) or x = 2\(\frac{1}{2}\)

C.

x = 1\(\frac{1}{2}\) or x = -1\(\frac{1}{2}\)

D.

x = -1\(\frac{1}{2}\) or x -2\(\frac{1}{2}\)

Correct answer is B

4x\(^2\) - 16x + 15 = 0

(2x - 3)(2x - 5) = 0

x = 1\(\frac{1}{2}\) or x = 2\(\frac{1}{2}\) 

11,973.

H varies directly as p and inversely as the square of y. If H = 1, p = 8 and y = 2, find H in terms of p and y.

A.

H = \(\frac{p}{4y^2}\)

B.

H = \(\frac{2p}{y^2}\)

C.

H = \(\frac{p}{2y^2}\)

D.

H = \(\frac{p}{y^2}\)

Correct answer is C

H \(\propto\) \(\frac{p}{y^2}\) 

H = \(\frac{pk}{y^2}\) 

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

k = \(\frac{4}{8}\)

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

H = \(\frac{p}{2y^2}\)

11,974.

If m : n = 2 : 1, evaluate \(\frac{3m^2 - 2n^2}{m^2 + mn}\)

A.

\(\frac{4}{3}\)

B.

\(\frac{5}{3}\)

C.

\(\frac{3}{4}\)

D.

\(\frac{3}{5}\)

Correct answer is B

m = 2, n = 1

\(\frac{3m^2 - 2n^2}{m^2 _ mn}\)

= \(\frac{3(2)^2 - 2(1)^2}{2^2 + 2(1)}\)

= \(\frac{12 - 2}{4 + 2} = \frac{10}{6}\)

= \(\frac{5}{3}\)

11,975.

Evaluate: 2\(\sqrt{28} - 3\sqrt{50} + \sqrt{72}\)  

A.

4\(\sqrt{7} - 21 \sqrt{2}\)

B.

4\(\sqrt{7} - 11 \sqrt{2}\)

C.

4\(\sqrt{7} - 9 \sqrt{2}\)

D.

4\(\sqrt{7} + \sqrt{2}\)

Correct answer is C

2\(\sqrt{28} - 3\sqrt{50} + \sqrt{22}\)

4\(\sqrt{7} - 15\sqrt{2} + 6\sqrt{2}\)

6\(\sqrt{7} - 9\sqrt{2}\)