Question

The average length of the eight words Betty was asked to spell was 9 letters. The first seven letters were 8 letters,9 letters,6 letters, 10 letters, 7 letters, 9 letters ,and 11 letters what was the length of the the eighth word

Answer 1

12 letters

The deviations from the average are -1, 0, -3, 1, -2, 0, 2, totaling -3. Hence the final word must be 3 letters longer than average.