Question

In a computer game, each move requires pressing a button. When the button is pressed for the first time, as a move, the computer randomly chooses a cell from a 4x4 grid of Sixteen cells and puts an "X" mark on that cell. When the button is pressed subsequently, the computer randomly chooses a cell from the remaining unmarked cells and puts an "X" mark on that cell. This goes on till the end of the game. The game ends when either all the cells in any one row, or all the cells in any one column, are marked with "X". What is the maximum possible number of times a player has to press the button to finish the game?

• A. 16
• B. 6
• C. 13
• D. 4
• E. 10

Hint:

Pigeonhole principle: With 4 rows, if you place 13 marks, at least one row will have 4 marks.

Answer 1

The Correct Option is C