WAEC Mathematics 2011 Paper

Concept:To simplify the given rational terms, express every fraction using a common denominator.Since $n \neq 0$, the least common denominator of $n$, $5n$, and $10n$ is $10n$.Explanation:Consider the expression $\frac{m}{n} + \frac{m-1}{5n} - \frac{m-2}{10n}$.Convert each term to the common denominator $10n$.$\frac{m}{n} = \frac{10m}{10n}$$\frac{m-1}{5n} = \frac{2(m-1)}{10n}$The third term remains $\frac{m-2}{10n}$.Combine the numerators over $10n$:$\frac{10m + 2(m-1) - (m-2)}{10n}$Simplify the numerator:$10m + 2m - 2 - m + 2 = 11m$Thus, the simplified expression is:$\frac{11m}{10n}$Answer:$\frac{11m}{10n}$, which is option B.