Question

There are 30 students in a class. One student weighing 25 kg goes away and a new student joins the class. If the average weight is then increased by 200 grams, what is the weight of new student ?

• A. 32 kg
• B. 31 kg
• C. 30 kg
• D. 29 kg

Answer 1

Answer:

B. 31 kg

As noted just above, the weight of the new student is 31 kg.

Weight of New Person = Weight of Removed Person + Total Number of People $\times$ Change in Average

Using your numbers:

Weight of New Person = $25\text{ kg} + (30 \times 0.2\text{ kg})$

Weight of New Person = 25 + 6 = 31 kg