C.40.JF:5.4 - All pairs fit but the whole combination does not

All pairs can fit while the whole set does not. In a separate arithmetic illustration, three non-shareable seven-hour activities each draw on one eighteen-hour budget. Every pair needs fourteen hours; all three need twenty-one. The deficit rules out that combination under those premises. It does not choose an optimal subset. The same issue arises when two six-hour demands compete for eight hours of shared capacity in an organization inquiry.