Multiple choice

The average of 13 results is 60. If the average of first 7 results is 59 and that of last 7 results is 61, what will be the seventh results

  1. 90

  2. 50

  3. 75

  4. 60
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D Correct answer
Explanation

Total sum of 13 results = 13 * 60 = 780. Sum of first 7 = 7 * 59 = 413. Sum of last 7 = 7 * 61 = 427. The 7th result is counted twice: (413 + 427) - 780 = 840 - 780 = 60.

AI explanation

The total sum of all 13 results is 13 multiplied by 60, which equals 780. The sum of the first 7 results is 7 multiplied by 59 to give 413, and the sum of the last 7 results is 7 multiplied by 61 to give 427. Adding these two sums gives 840, but since the 7th result is counted twice, you subtract the overall sum of 780 from 840 to find the 7th result, which is 60.

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