Question

ab : bc is 2:5

Explanation:

Step1: Set up the proportion

Since \(AB:BC = 2:5\), let \(AB = 2k\) and \(BC=5k\). Given \(BC = 20\), then \(5k=20\).

Step2: Solve for \(k\)

Divide both sides of \(5k = 20\) by \(5\): \(k=\frac{20}{5}=4\).

Step3: Find \(AB\)

Since \(AB = 2k\) and \(k = 4\), then \(AB=2\times4 = 8\).

Answer:

\(x = 8\)