Multiple choice

The average weight of 15 girls was recorded as 54 kg. If the weight of the teacher was added, the average increased by two kg. What was the teacher's weight?

  1. 75 kg

  2. 95 kg

  3. 78 kg

  4. 86 kg
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total weight of 15 girls = 15 × 54 = 810 kg. With teacher, total weight = 16 × 56 = 896 kg (average increases by 2 kg). Teacher's weight = 896 - 810 = 86 kg. Option A (75 kg) assumes adding only 21 kg, which doesn't change the average correctly.

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