A student uses 50 custom-made wooden cubes, each with exactly one face painted red, to model the radioactive decay of a sample of unstable nuclei.

They carry out the following method:

1. Roll all 50 cubes onto a flat tray.
2. Remove any cubes that land with the red face pointing upwards (representing decayed nuclei).
3. Record the number of remaining cubes.
4. Roll the remaining cubes.
5. Repeat this process six more times.