Total length of the wire, L=114 cm n1:n2:n3=1:3:4 Let L1, L2 and L3 be the lengths of the three parts As n∝ L1 ∴L1:L2:L3=11:31:41=12:4:3∴L1=72 cm(12+4+312×114)L2=24 cm(194×114) and L3=18 cm(193×114) Hence the bridges should be placed at 72 cm and 72+24=96 cm from one end.