The average weight of 3 persons A, B and C is 60 kg. When D joins the group, the average weight becomes 65 kg. When another person E whose weight is 3 kg less than that of D replaces A. the average weight of B, C, D and E becomes 67 kg. What is the weight of A ? |
60 kg 69 kg 72 kg 65 kg |
69 kg |
Sum of weight of , A + B + C = 3 × 60 = 180 kg D joins the group , A + B + C + D = 4 × 65 = 260 kg -----(1) Weight of D = 260 - 180 = 80 kg Weight of E = 80 - 3 = 77 kg Sum of weight of , B + C + D + E = 4 × 67 = 268 kg ----(2) Put value of E in equation 2 B + C + D = 268 - 77 = 191 kg By putting sum of B , C & D in equation 1 Weight of A = 260 - 191 = 69 kg |