The average age of 30 students is 9 years. If the age of their teacher is included, the average age becomes 10 years. The age of the teacher (in years) is :
A. 27
B. 31
C. 35
D. 40
Answer: Option D
Solution (By Examveda Team)
Let the age of teacher = x yearsAccording to the question,
30 × 9 + x = 31 × 10
270 + x = 310
x = 40 years
This Question Belongs to Arithmetic Ability >> Average
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