WAEC Mathematics Past Questions & Answers - Page 103

% error = \(\frac{error}{\text{actual value}} \times 100\)

error = N72 - N68 = 4

actual value = N72

%error = \(\frac{4}{72} \times 100\)

= \(\frac{100}{18} = \frac{50}{9}\) = 5\(\frac{5}{9}\)%

\(\sqrt{50} - K\sqrt{8} = \frac{2}{\sqrt{2}}\)

\(\sqrt{50} - \frac{2}{\sqrt{2}}\) = K\(\sqrt{8}\)

= \(\sqrt{2} \times 25 - \frac{2}{\sqrt{2}}\)

= K \(\sqrt{4 \times 2}\)

\(\frac{5\sqrt{2}}{1} - \frac{2}{\sqrt{2}}\) = 2K\(\sqrt{2}\)

\(\frac{5\sqrt{4} - 2}{\sqrt{2}} = 2K\sqrt{2}\)

\(\frac{10 - 2}{\sqrt{2}} = 2K \sqrt{2}\)

\(\frac{8}{\sqrt{2}} = \frac{2K\sqrt{2}}{1}\)

= 2k\(\sqrt{2} \times \sqrt{2}\) = 8

2k \(\sqrt{4}\) = 8

2k x 2 = 8

4k = 8

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

k = 2

Un = n(n² + 1)

U⁵ = 5(² + 1)

= 5(25 + 1)

= 5(26) = 130

U⁴ = 4(4² + 1) = 4(16 + 1)

= 4(17) = 68

U5 - U4 = 130 - 68

= 62

\(\frac{1\frac{7}{8} \times 2\frac{2}{5}}{6\frac{3}{4} \div \frac{3}{4}}\)

from numerator \(1 \frac{7}{8} \times 2 \frac{2}{5}\)

= \(\frac{15}{8} \times \frac{12}{5}\)

= \(\frac{3 \times 3}{2 \times 1} = \frac{9}{2}\)

from denominator \(6\frac{3}{4} \div \frac{3}{4}\)

= \(\frac{27}{4} \div \frac{3}{4}\)

= \(\frac{27}{4} \times \frac{4}{3}\)

= \(\frac{9 \times 1}{1 \times 1} = \frac{9}{1}\)

\(\frac{9}{2} \div \frac{9}{1} = \frac{9}{2} \times \frac{1}{9}\)

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

No explanation has been provided for this answer.