GMAT Question of the Day - Problem Solving - Puzzle
If each term of the sequence K1 + K2 + ... + Kn is either 9 or 99 and the sum of the sequence is 495 which of the following could be a value of n^2?
GMAT Question of the Day Solution
This is a great time to make a chart so that you can see what your options are. Take your time and be organized with this. It may take you an extra few seconds to get started but being methodical will pay off. Start at the extreme using only 9's and build your way up. You should start to notice a pattern developing. All of the values for n end in 9. We'll be looking for n squared so the answer must end in 5. Eliminate B, D, and E. We have two choices but one is greater than the maximum 55*55. You can do the multiplication using distribution.