The branch and bound tree Figure 12.10 records solution of the knapsack model min 90x1 + 50x2 + 54x3 s.t. 60x1 + 110x2 + 150x3 Ú 50 x1, x2, x3 = 0 or 1 by LP-based Algorithm 12A under rules of Exercise 12-22.

Briefly describe the processing, including how and why nodes were branched or terminated, when incumbent solutions were discovered, and what solution proved optimal. Assume that there was no initial incumbent solution.