Two steel plates each of width 150 mm and thickness 10 mm are connected with three 20 mm diameter rivets placed in a zig-zag pattern. The pitch of the rivets is 75 mm and gauge is 60 mm. If the allowable tensile stress is 150 MPa, the maximum tensile force that the joint can withstand is

ANS:C - 192.75 kN

We have to take all the possibilities and look for the minimum area, when we are taking section along a single bolt the area comes out as 1285mm2, similarly along the section containing both the bolts the area comes out as 1070mm2, and while taking the section along zig zag arrangement, area comes out as 1323.75mm2, accordingly we have to take critical area ie minimum which is 1070 and multiply it by 150, but the sol is not in the options, don't understand why, in the sol the second lowest value ie 1285 has been taken and multiplied by 150, could someone elaborate. ?