The tension T in the cable is 354.9 Newtons as the box of nails lies on scaffold 2 which is centered at distance from the left end.
L1 is the Distance from the pivot point where the cable is attached to scaffold 1 to the point where the cable connects to scaffold 2 is 1.5 m. The pivot point is at the end of scaffold 1 where the cable is attached.
we now go ahead to calculate the torques:
Torque due to T (clockwise): T * 1.5
Torque due to m2g (counterclockwise): 27g * (1.5 + 2.4/2) = 27g * 2.7
Torque due to box of nails (counterclockwise): 15g * (1.5 + 0.65) = 15g * 2.15
Torque due to m1g (clockwise): 53g * (1.5/2) = 53g * 0.75
Στ = 0
T * 1.5 - 27g * 2.7 - 15g * 2.15 + 53g * 0.75 = 0
T = (27g * 2.7 + 15g * 2.15 - 53g * 0.75) / 1.5
T ≈ 354.9 N