WAEC Past Questions and Answers - Page 3930

19,646.

Simplify \(\left(\frac{16}{81}\right)^{-\frac{3}{4}}\times \sqrt{\frac{100}{81}}\)

A.

\(\frac{80}{243}\)

B.

\(\frac{1}{64}\)

C.

\(\frac{25}{6}\)

D.

\(\frac{15}{4}\)

Correct answer is D

\(\left(\frac{16}{81}\right)^{-\frac{3}{4}}\times \sqrt{\frac{100}{81}}\\
\frac{1}{\left(\sqrt[4]{\frac{16}{81}}\right)^3}\times \frac{10}{9}=\frac{1}{\left(\frac{2}{3}\right)^3}\times\frac{10}{9}\\
=\frac{27}{8}\times \frac{10}{9}=\frac{15}{4}\)

19,647.

What fraction must be subtracted from the sum of \(2\frac{1}{6}\) and \(2\frac{7}{12}\) to give \(3\frac{1}{4}\)?

A.

\(\frac{1}{3}\)

B.

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

C.

\(1\frac{1}{6}\)

D.

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

Correct answer is D

\(2\frac{1}{6} + 2\frac{7}{12}\)

= \(\frac{13}{6} + \frac{31}{12}\)

= \(\frac{26 + 31}{12}\)

= \(\frac{57}{12} = \frac{19}{4}\)

\(\frac{19}{4} - 3\frac{1}{4}\)

= \(\frac{19}{4} - \frac{13}{4}\)

= \(\frac{6}{4}\)

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

19,648.

Find the missing number in the addition of the following numbers, in base seven
\(\begin{matrix}
4 & 3 & 2 & 1\\
1 & 2 & 3 & 4\\
* & * & * & *\\
1&2&3&4&1
\end{matrix}\)

A.

3453

B.

5556

C.

6016

D.

13453

Correct answer is A

4321\(_7\) + 1234\(_7\) = 5555\(_7\)

Missing number = 12341\(_7\) - 5555\(_7\)

= 3453\(_7\)

19,649.

Simplify \(\frac{10}{\sqrt{32}}\)

A.

\(\frac{5}{4}\sqrt{2}\)

B.

\(\frac{4}{5}\sqrt{2}\)

C.

\(\frac{5}{16}\sqrt{2}\)

D.

\(\frac{16}{5}\sqrt{2}\)

Correct answer is A

\(\frac{10}{\sqrt{32}}=\frac{10}{\sqrt{16\times 2}} = \frac{10}{4\sqrt{2}}\\
\frac{10\times \sqrt{2}}{4\sqrt{2}\times\sqrt{2}}=\frac{10\sqrt{2}}{4\times 2}= \frac{5}{4}\sqrt{2}\)

19,650.

Soil factors in an ecosystem are referred to as

A.

topographic

B.

climatic

C.

biotic

D.

edaphic

Correct answer is D

No explanation has been provided for this answer.