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The average age of a class of 20 students is 16 years. When the teacher is included, the average rises to 17. The teacher's age is
A35 years
B36 years
C37 years
D38 years
Answer & Solution
Correct answer: C. 37 years
Old sum of ages = 20 x 16 = 320. New sum (with teacher) = 21 x 17 = 357. Teacher's age = 357 - 320 = 37.
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