Three cars travelled distance in the ratio 1 : 2 : 3. If the ratio of the time of travel is 3 : 2 : 1, then the ratio of their speed is -
1
3 : 9 : 1
2
1 : 3 : 9
3
1 : 2 : 4
4
4 : 3 : 2
Three cars travelled distance in the ratio 1 : 2 : 3. If the ratio of the time of travel is 3 : 2 : 1, then the ratio of their speed is -