In this problem, we need to use the concept of proportions. Proportion says that two ratios (or fractions) are equal. So, we have two numbers, namely:
\(x=8 \ and \ y=20\)
So, the given proportion is:
\(\frac{x}{y}=\frac{8}{20} \\ \\ \therefore \frac{x}{y}=\frac{2}{5}\)
That is, x-out-of-y is equal to 2-out-of-5
On the other hand, we know that \(x=42\), so by using the previous proportion we have:
\(\frac{42}{y}=\frac{2}{5} \\ \\ Isolating \ y: \\ \\ y=\frac{42 \times 5}{2} \\ \\ y=\boxed{105}\)
