The mitotic index counter

A student counts the cells of a root tip and writes the number in each stage in a dictionary. You will find the mitotic index, the minutes that a cell spends in a stage, and the stage that takes the longest.

The idea. If the cells divide at random, the share of cells in a stage is the share of the cycle that the stage takes.

Your tasks.

1. Finish mitotic_index. It gives the per cent of the cells that are in mitosis. Interphase is not mitosis.
2. Finish minutes_in. It gives the minutes that a cell spends in one stage, for a cycle of cycle_hours.
3. Finish longest. It gives the name of the mitotic stage that takes the longest.