There are 116,280 different ways that the club can select its officers
Here, we have 20 members of which we want to select 4 officers
From the question, without any issue, we are selecting 4 from 20
The condition here is that nobody can hold more than a single position
For the office of the president;
The 20 members can vie for it, so we have 20 choices to select from
For the office of the vice president;
We have 19 members left (1 is already selected as president); so we have 19 choices to select from
For the office of the treasurer;
We have only 18 choices left (2 positions are filled already)
For the position of the secretary;
We have 17 choices to pick from (3 positions are filled already)
The total number of ways we can make selection is thus;