The average age of 9 students and their teacher is 16 yr. The average age of the first four students is 19 yr and that of the last five is 10 yr. The teacher's age is

A) 36 yr

B) 34 yr

C) 30 yr

D) 28 yr

Correct answer:
B) 34 yr

Description for Correct answer:
Total age of 9 students and a teacher = 10 x 16 = 160 yr

Total age of first 4 students = 4 x 19 = 76 yr

and total age of last 5 students = 5 x 10 = 50 yr

Age of teacher = 160 - 76 - 50 = 34


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