To solve for shear stress, start with the total load of 80 kiloNewtons and recognize that each bolt experiences double shear, meaning each bolt's shear force is half the total load. The average shear stress can be calculated by dividing the shear force by the cross-sectional area of the bolt. Given the allowed shear stress and the total load, the unknown diameter of the bolts can be determined using the appropriate formula. It’s important to account for both cross-sectional areas when calculating the shear stress for multiple bolts. Understanding these principles will help in effectively solving shear stress problems.