The average weight of Somdev, Gurdeep and Ritu is 85 kg. If the average weight of Somdev and Gurdeep be 79 kg and that of Gurdeep and Ritu be 73 kg, then the weight of Gurdeep is

Let respective weights of Somdev, Gurdeep and Ritu is $$s , g , r$$ kg

Average weight of the three = $$\frac{s + g + r}{3} = 85$$

=> $$s + g + r = 85 \times 3 = 255$$ kg --------------(i)

Similarly, Total weight of Somdev and Gurdeep = $$s + g = 79 \times 2 = 158$$ kg ---------------(ii)

Total weight of Gurdeep and Ritu = $$g + r = 73 \times 2 = 146$$ kg -------------(iii)

Adding equations(ii) and (iii), => $$s + 2g + r = 158 + 146 = 304$$ ---------------(iv)

Subtracting equation (i) from (iv), we get :

=> $$g = 304 - 255 = 49$$ kg