Question
Download Solution PDFThe average age of students in a class was 15 years. When 5 new boys whose average age was 12 years 6 months were admitted in the class, the average age was reduced by 6 months. How many students were there in the class originally?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFGiven:
The average age of students in a class = 15 years
The average age of 5 new students in a class = 12.5 years
Formula used:
Average = Sum of all values/ No. of values.
Calculation:
Let the number of students in the class be x.
The new average = 15 - 0.5(6 months) = 14.5 years.
⇒ (x × 15) + (5 × 12.5) = (x + 5) × 14.5
⇒ 15x + 62.5 = 14.5x + 72.5
⇒ 0.5x = 10
⇒ x = 20
∴ The correct answer is 20.
Last updated on Jul 4, 2025
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