BECE Mathematics 2019 Paper

Concept:A proportion means two ratios are equal. Write each ratio as a fraction, then cross multiply to find the unknown value.Explanation:The statement $6:8 = r:48$ can be written as two equal fractions.So, $6:8 = \frac{6}{8}$ and $r:48 = \frac{r}{48}$.This gives the equation $\frac{6}{8} = \frac{r}{48}$.Now cross multiply the fractions. Multiply the numerator on the left by the denominator on the right.$6 \times 48 = 8 \times r$Simplifying the left side: $288 = 8r$Divide both sides by $8$ to make $r$ the subject.$r = \frac{288}{8}$$r = 36$Answer:The value of $r$ is $36$, which is option A.