Take the 50 museum visitors of the first problem: bus 20, car 15, train 10 and on foot 5.

Step 1. Bus. $\dfrac{20}{50} = \dfrac{2}{5} = 0.4$.

Step 2. Car. $\dfrac{15}{50} = \dfrac{3}{10} = 0.3$.

Step 3. Train and on foot. $\dfrac{10}{50} = \dfrac{1}{5} = 0.2$, and $\dfrac{5}{50} = \dfrac{1}{10} = 0.1$.