The average weight of a class of 30 students is 45 kg. One of the students whose weight is 48.5 kg is replaced by another student and the average weight was increased by 200 g. Find the weight of the new student.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 54.5 kg.
Initial average = 45 kg
Total weight = 30 × 45 = 1350 kg
One student of 48.5 kg is replaced.
New average = 45 + 0.2 = 45.2 kg (since 200 g = 0.2 kg)
New total weight = 30 × 45.2 = 1356 kg
Difference in total weight = 1356 − 1350 = 6 kg
So, weight of new student = 48.5 + 6 = 54.5 kg