The ratio of the speed of three cars is 3 ∶ 4 ∶ 5, What will be the ratio of time taken by those three cars to cover the same distance?
1. 5 ∶ 4 ∶ 3
2. 20 ∶ 15 ∶ 12
3. 15 ∶ 12 ∶ 20
4. 4 ∶ 5 ∶ 3