Practise the method.Example 1A vehicle travels 420km in 7 hours at a steady rate. How far does it travel in 6 hours?Show worked answerAnswer: 360Rate =7420=60km/h. Distance =60×6=360km.Example 2A map scale is 1:4000. A line is 3cm on the map. Find its real length in metres.Show worked answerAnswer: 120Real length =3×4000cm. Divide by 100 centimetres per metre to get 120m.Example 3y is directly proportional to x. When x=6,y=12. Find y when x=3.Show worked answerAnswer: 6The constant is xy=2, so y=2x. At x=3,y=6.