The average age of 10 students and their teacher is 15 years. The average age…
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The average age of 10 students and their teacher is 15 years. The average age of the first seven students is 15 yr and that of the last three is 11 yr. What is the teacher's age?
- A.
33 years
- B.
30 years
- C.
24 years
- D.
27 years
Attempted by 1628 students.
Show answer & explanation
Correct answer: D
Total Age of 10 students and Teacher = 11 x 15 = 165
Total age of first 7 students = 7 x 15 = 105
Total age of 3 students = 3 x 11 = 33
Thus total age of students = 33 + 105 = 138
Age of Teacher = 165 - 138 = 27