### The average weight of 3 men, A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If another man E whose weight is 3 kg more than that of D, replaces A then the average weight of B, C, D and E becomes 79 kg. What is the weight of A ?

A. 70 kg

B. 72 kg

C. 75 kg

D. 80 kg

$\begin{array}{l}\text{A + B + C = 84 × 3 = 252…..(i)}\\ \text{A + B + C + D = 80 × 4 = 320…..(ii)}\\ \text{On solving equation (i) and (ii)}\\ \text{D = 320 – 252}\\ \text{D = 68}\\ \text{E’s weight = 68 + 3 = 71}\\ \text{B + C + D + E = 79 × 4 = 316}\\ \text{B + C + D + 71 = 316}\\ \text{B + C + D = 316 – 71 = 245}\\ \text{Now, from equation (ii)}\\ \text{(A + B + C + D) – (B + C + D)}\\ \text{A = 320 – 245}\\ \text{∴ A = 75 kg}\end{array}$