The average of nine numbers is 50. The average of the first five numbers is 54 and the average of the last three numbers is 52. Find the sixth number of this set of numbers?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 24
An average times the number of values gives their total. The first five and the last three numbers together leave out only the sixth, so the sixth number is the whole total minus these two totals.
Total of all nine \(=9\times50=450\)
Total of the first five (1st to 5th) \(=5\times54=270\)
Total of the last three (7th to 9th) \(=3\times52=156\)
Sixth number \(=450-270-156=24\)