The average of 11 results is 50. If the average of the first six results is 49 and that of the last six results is 52, what is the sixth result?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 56
The first six and the last six results together cover all 11 results, with the sixth result counted twice. So the sum of the two group totals exceeds the total of all 11 results by exactly the sixth result.
Total of all 11 results \(=11\times50=550\)
Total of the first six \(=6\times49=294\)
Total of the last six \(=6\times52=312\)
Sixth result \(=294+312-550=56\)
The sixth result is 56.