A researcher randomly selects 3 fish from among 8 fish in a tank and puts each of the 3 selected fish into different containers. how many ways can this be done?

First he can select one fish among 8, after that one among 7 of them and finally one among 6 fish.

8 * 7 * 6 = 336

Then he puts each of selected fish into different containers:

336 * 3 * 2 * 1 = 2,016

Answer: This can be done in 2,016 ways.