Answer:
The ratio of how much they have watched to how much they have left to see is 4 : 1.
Step-by-step explanation:
Consider that the total duration of the film is, 1.
It is provided that James and Cameron paused when there is one-fifth left to watch.
That is, they have already watched, th of the film.
Compute the ratio of how much they have watched to how much they have left to see as follows:
Thus, the ratio of how much they have watched to how much they have left to see is 4 : 1.