Capital Co. is considering 5 different projects. Define Xi as a binary variable that equals 1 if project i is undertaken and 0 otherwise, for =1,2,3,4,5i=1,2,3,4,5.

Write down the constraint(s) stating that: at most one of projects 1, 3, and 5 can be undertaken simultaneously, while either project 1 or 2 must be done definitely (both could be done as well).