A table of the given information is formed as

Number of hours | 4 | 8 | 12 | 24 |

Parking charges (in Rs) | 60 | 100 | 140 | 180 |

The ratio of parking charges to the respective number of hours (Rs/ hour) can be calculated as

As each ratio is not same, therefore, the parking charges are not in a direct proportion to the parking time.