Drop box

Consider a capital budgeting problem with seven project represented by binary (0 or 1) variables X1, X2, X3, X4, X5, X6, X7.

Write a constraint modeling the situation in which at most 4 projects from projects 2, 3, 4, 5, 6, and 7 can be selected.

Write a constraint modeling the situation in which only 2 of the projects from 2, 3, 4, and 5 must be selected.

Write a constraint modeling the situation project 3 or 6 must be selected, but not both .

Write a constraint modeling the situation in which at least 3 of the projects from 1, 2, 5, and 7 must be selected.