1. The problem statement, all variables and given/known data In the example A , Why the author stated the total reactions = 9 only ? How to determine the total reactions for this type of questions ? 2. Relevant equations 3. The attempt at a solution we can see that there is a total of 3 reactions (vertical , horizontal and moment) at the cut of the 4 parts , right (circled part) , and 3 reactions below . So , the total reactions is 4x3 + 3 = 15.