JAMB Mathematics 2015 Paper

Concept:Convert mixed numbers to improper fractions, then combine them using a common denominator.Explanation:Change each mixed number into an improper fraction.$6\frac{1}{12} = \frac{73}{12}$$2\frac{3}{4} = \frac{11}{4}$$1\frac{1}{2} = \frac{3}{2}$The lowest common denominator for $12$, $4$, and $2$ is $12$.Rewrite the second and third fractions with denominator $12$.$\frac{11}{4} = \frac{33}{12}$ and $\frac{3}{2} = \frac{18}{12}$Now combine the numerators:$\frac{73}{12} - \frac{33}{12} + \frac{18}{12} = \frac{58}{12}$Simplify the fraction:$\frac{58}{12} = \frac{29}{6}$Convert the improper fraction back to a mixed number:$\frac{29}{6} = 4\frac{5}{6}$Answer:$4\frac{5}{6}$This matches Option B.