The average weight of 12 persons increases by 2.5 kg when a new person comes in place of one of them weighing 48 kg. The weight of the new person is:
Answer & explanation
Correct answer: option 4
Let the average of 12 people be x kg
And the weight of the new person be y kg
Sum of 12 people weight is
12 × x = 12x kg
When the person is replaced.
12x + y - 48 = 12 × (x + 2.5 )
12x + y - 48 = 12x + 30
y = 48 + 30 = 78 kg
∴ The weight of the new person is 78 kg.