Multiple choice

The average age of 15 students is 18 years. If the teacher's age is added, the average increases by 1 year. What is the teacher's age?

  1. 32 years

  2. 34 years

  3. 35 years

  4. 33 years

  5. 30 years
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total age of 15 students = 15 * 18 = 270. Total age with teacher = 16 * 19 = 304. Teacher's age = 304 - 270 = 34.

AI explanation

The total age of the 15 students is 15 times 18, equaling 270 years. When the teacher is added, there are 16 people and the new average becomes 19 years, making the new total age 16 times 19, equaling 304 years. The teacher's age is the difference between the new total and the old total, which is 304 minus 270. Therefore, the teacher's age is 34 years.

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