WAEC Mathematics 2021 Paper

Concept:Convert each mixed number into an improper fraction, then divide the total sum by the number of values to find the mean.Explanation:The given numbers are:$1\frac{1}{2}, 2\frac{2}{3}, 3\frac{3}{4}, 4\frac{4}{5}, 5\frac{5}{6}$Write each mixed number as an improper fraction:$1\frac{1}{2}=\frac{3}{2}, \quad 2\frac{2}{3}=\frac{8}{3}, \quad 3\frac{3}{4}=\frac{15}{4}, \quad 4\frac{4}{5}=\frac{24}{5}, \quad 5\frac{5}{6}=\frac{35}{6}$Find the sum of these fractions using the least common denominator $60$:$\frac{3}{2}+\frac{8}{3}+\frac{15}{4}+\frac{24}{5}+\frac{35}{6}$$=\frac{90+160+225+288+350}{60}$$=\frac{1113}{60}=18.55$There are 5 numbers, so the mean is:$\frac{18.55}{5}=3.71$Answer:The mean, correct to two decimal places, is $3.71$.Correct option: A. 3.71