The average weight of A, B, C and D is 40 kg. A new person E is also included in the group, then the average weight of the group is increased by 1 kg. Again, a new person F replaces A, then the new average of 5 persons becomes 42. The average weight of B, C, D and F is: A, B, C और D का औसत भार 40 किग्रा है। एक नए व्यक्ति E को भी समूह में शामिल किया जाता है, तो समूह के औसत वजन में 1 किग्रा की वृद्धि होती है। फिर से, एक नया व्यक्ति F, A की जगह लेता है, तो 5 व्यक्तियों का नया औसत 42 हो जाता है। B, C, D और F का औसत वजन है:

Initial: A+B+C+D = 4×40 = 160 kg. With E: A+B+C+D+E = 5×41 = 205 kg. So E = 205-160 = 45 kg. After F replaces A: B+C+D+E+F = 5×42 = 210 kg. But we know B+C+D+E = 205 kg, so F = 210-205 = 5 kg. We need B+C+D+F. From A+B+C+D = 160, we need A. With E added, average increased by 1 kg for 5 people, so E = 40+5 = 45 kg (checking out). From B+C+D+E+F = 210, substituting: (160-A) + 45 + 5 = 210, giving 210-A = 210, so A = 0 kg. Then B+C+D+F = 160-0+5 = 165 kg. Average = 165/4 = 41.25 kg. Wait - A = 0 is impossible. There's an inconsistency. Let me re-examine: When E is added to 4 persons, average increases by 1, so E must be 40 + 5 = 45 kg. After F replaces A: B+C+D+E+F = 210. We know B+C+D+E = 205 (since that's the group when E was added). So F = 210-205 = 5 kg. B+C+D+F = (B+C+D+E+F) - E = 210 - 45 = 165. Average = 165/4 = 41.25. This matches option B.