The cell cycle clock

A list gives the phases of a cell cycle and the hours of each. You will find the length of the cycle, the share of interphase, and the phase that a cell is in at a given hour.

The idea. The cycle repeats. A cell at 25 h of a 24 h cycle is 1 h into its next cycle.

Your tasks.

1. Finish total_time. It gives the hours of the whole cycle.
2. Finish interphase_share. It gives the per cent of the cycle that is not M.
3. Finish phase_at. It gives the name of the phase that the cell is in t hours after it was formed.