find number of ways to place 5 letters L1,L2,L3,L4 and L5 in 5 different envelopes E1,E2,E3,E4 and E5, such that L1 goes to E2 and L2 goes to E3 and no other letter goes to its correct envelope Share with your friends Share 0 Vijay Kumar Gupta answered this We are given five letters L1, L2, L3, L4 and L5 and five different envelopes E1,E2, E3, E4, E5We need to put L1 into E2, L2 into E3 and no other letter goes to its correct envelope.Note that here L1, L2, E2 and E3 has been already used. These are fixed.So we need to put the remaining letters L3, L4 and L5 into E1, E4 and E5 such that no one goes in the correct envelope.Now L3 can be put in any of the wrong envelope E1, E4 and E5, so we have 3 choices here.If L3 is put into E1, then we are left with E4 and E5, so that L4 can be put into E5 and L5 can be put into E4If L3 is put into E4, then we are left with E1 and E5, so that L4 can be put into E5 and L5 can be put into E1If L3 is put into E5, then we are left with E1 and E4, so that L4 can be put into E1 and L5 can be put into E4Thus we have always three choices for letter L3, 1 choice for L4 and 1 choice for L5.Thus the total number of ways are, 3×1×1=3 0 View Full Answer