Multiple choice

The average age of 18 girls and their teacher is 17 years. If the teacher's age is excluded, the average reduces by 2. What is the teacher's age?

  1. 35 years

  2. 43 years

  3. 53 years

  4. 36 years

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sum of ages of 18 girls and teacher = 19 * 17 = 323. Sum of ages of 18 girls = 18 * (17 - 2) = 18 * 15 = 270. Teacher's age = 323 - 270 = 53.

AI explanation

The total age of the 18 girls and the teacher is 19 multiplied by 17, which is 323 years. When the teacher is excluded, the total age of the 18 girls is 18 multiplied by 15, giving 270 years. The teacher's age is the difference between these two totals, which is 323 minus 270, or 53 years.

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