Admission changes average weight: The average of 19 students is 15 kg. After admitting one new student, the new average becomes 14.8 kg. Find the weight of the new student.
Aptitude
Average
Difficulty: Easy
Choose an option
Answer
Correct Answer: 11 kg
Explanation
Introduction / Context:Average shift problems involving the addition of one value are solved by recomputing totals before and after the change. The difference equals the added value.
Given Data / Assumptions:
- Initial: 19 students, average 15 kg
- After addition: 20 students, average 14.8 kg
Concept / Approach:Compute initial total, compute new total, subtract to get the new student’s weight.
Step-by-Step Solution:
Initial total = 19 * 15 = 285 kgNew total = 20 * 14.8 = 296 kgWeight of new student = 296 - 285 = 11 kgVerification / Alternative check:With the new student at 11 kg, the total becomes 296 over 20 students, giving 14.8 kg average as stated.
Why Other Options Are Wrong:
- 10.6, 10.8, 14.9, 12.5 kg: do not produce the new average when recalculated.
Common Pitfalls:Using 19 in the second multiplication by mistake or misplacing decimals when multiplying 14.8 by 20.
Final Answer:11 kg