The average weight of 8 person's increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. What might be the weight of the new person?

Problem Restatement

A replacement increases the average of 8 people by 2.5 kg. Find the new person's weight if the outgoing person weighed 65 kg.

Concept / Approach

When the average of n people increases by Δ, the total sum increases by nΔ. Here, n = 8 and Δ = 2.5 → total increase = 8 × 2.5 = 20 kg.

Step-by-step calculation

Increase in total due to replacement = 20 kgTherefore, New weight − Old weight = 20New weight = 65 + 20 = 85 kg

Check

• Average increases by 20 ÷ 8 = 2.5 kg, consistent with the problem.

Final Answer

Weight of the new person = 85 kg.