Answer:
The ratio of how much they have watched to how much they have left to see is 4 : 1.
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:
![\frac{\text{Duration Watched}}{\text{Duration Left}}=(4/5)/(1/5)=(4)/(1)=4:1](https://img.qammunity.org/2021/formulas/mathematics/college/fb47vasnh3w1p6rmc582r16d99gopxqoxz.png)
Thus, the ratio of how much they have watched to how much they have left to see is 4 : 1.