The average age of 10 students in a class increases by 1 year when a 30-year-old teacher joins them. What was the original average age of the students?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 19
Let the original average age of 10 students be x years.
Total age of students = 10x
When the 30-year-old teacher joins, total members = 11
New average = x + 1
10x + 30 = 11(x + 1)
10x + 30 = 11x + 11
x = 19
Therefore, the original average age of the students was 19 years.