Question

There are 40 students in a class. Their average weight is 60 kg. Two students left the class. Then the average weight is reduced by 500 g. Find the weight of the two students who left the class (in kg).

• A. 140
• B. 130
• C. 129
• D. 139

Answer 1

Answer:

D. 139

Initial total weight of 40 students:
$40 \times 60 = 2400 \text{ kg}$

After 2 students leave:

• Remaining students = 38

• New average = (60 - 0.5 = 59.5) kg

New total weight:
$38 \times 59.5 = 2261 \text{ kg}$

Weight of the two students who left:
$2400 - 2261 = 139 \text{ kg}$
Final Answer: 139 kg