The average weight of 10 persons increases by 3.5 kg when a new person comes in place of one of them weighing 85 kg. What might be the weight of the new person?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 120 kg.
Let the total weight of the original 10 persons be x
The average weight of the 10 persons increases by 3.5 kg
New average = Old average + 3.5
The new total weight of the 10 persons = x + 10 × 3.5 = S + 35
When a new person replaces one weighing 85 kg, the total weight changes to S + 35
⇒ S - 85 + x = S + 35
⇒ -85 + x = 35
⇒ x = 120
Hence, The weight of the new person is 120 kg