Let’s look at the two questions. If there are 24 senators, two-thirds of 24 equals 16 votes. Now, if four senators are unable to vote, does the number automatically become 20? Not necessarily. The Constitution refers to two-thirds of all the Members of the Senate. So, 16 is the mathematical answer for 24 senators, while 14 would only apply if the law allows the calculation to be based on 20 senators. In the end, this question depends on legal interpretation and the decision of the proper authorities.