1. The average age of 10 students in a class is 15 years. One student leaves and the average becomes 14.5 years. What is the age of the student who left?
Show Answer
Answer: 19.5 years old
Explanation
Answer :
No. of students in a class = 10.
Average age of all 10 students = 15 years
No. of students left =1
Remaining No.of students = 9
Average of 9 students = 9
Total age of 10 students = 10×15=15010×15=150years.
After one student left, total age of 9 students = 9×14.5=130.59×5=130.5years.
Age of student who left = 150−130.5=19.5 years.
So, the student who left was 19.5 years old.
