Multiple choice

The sum of the ages of 75 girls of a class is 1050 years. Out of these, the average age of 25 girls is 12 years and the average age of other 25 girls is 16 years. The average age of the remaining girls is:

  1. 12 years

  2. 13 years

  3. 14 years

  4. 15 years
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total sum = 1050. Sum of 25 girls = 25 * 12 = 300. Sum of next 25 girls = 25 * 16 = 400. Remaining girls = 75 - 25 - 25 = 25. Sum of remaining = 1050 - 300 - 400 = 350. Average = 350 / 25 = 14.

AI explanation

The total weight of the fourth and fifth experiments is 0.010 less than 54.005, giving an average of 53.995, so their sum is 107.990. The total weight of all 7 experiments is 53.735 times 7, which equals 376.145. The total of the first three is 162.015, making the combined total of the first five experiments 269.005. This leaves the fourth experiment as 269.005, which is 53.072.

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