Practicing Success
The average weight of 10 persons increases by 2 kg when a new person comes in place of one of them weighing 55 kg. The weight of the new person is: |
85 70 75 80 |
75 |
Let the average of 10 people be x kg And the weight of the new person be y kg Sum of 10 people weight is 10× x = 10x kg When the person is replaced. 10x + y - 55 = 10 × (x + 2) 10x + y - 55 = 10x + 20 y = 55 + 20 = 75 kg ∴ The weight of the new person is 75 kg. |