Sierra Lumber Company produces lumber. The company has two grades of lumber at the split-off point, A and B. Grade A sells for exist4 per board foot and Grade B sells for exist2 per board foot. This lumber is suitable for framing and most exterior work but no for the interior of buildings. Either grade can be further processed to make it suitable for interior work at a cost of exist1.20 per board foot. After this further processing, the firm can sell Grade A lumber for exist5.50 per board foot and Grade B for exist3.00 per board foot. Would you recommend the company sell the lumber at the split-off point or process it further to make it suitable for interior work? Explain and give supporting computations