Find the efficiency of the following riveted joints: (a) Single riveted lap joint of 3mm plates with mm diameter rivets having a pitch of 20mm and (b). Double riveted lap joint of 6mm plates with 30mm diameter having a pitch of 35mm.Assume permissible tensile stress in plate =140MPa., Permissible shearing stress in rivets =105MPa, Permissible crushing stress in rivets =250MPa.​