Okay, this question is asked in a Google Interview!! Very Intelligent Question...
Assuming an 8X8 Chessboard with the usual colouring of black and white squares.You may repaint all squares (a)of a row (b) of a 2X2 square.The goal is to attain one black square.Can you reach the goal??
(Logical Explanation required)
Please don't give vague answers like yes or no.

• a)If we color each row with black,finally we end up with one black square...!
  b)Same applied to 2x2 also.
• 10 years agoHelpfull: Yes(6) No(4)
• (a)color all the black squares of a row with white color except one.
  (b)color one of the black square in a 2*2 square with white color and the remaining will be one black square.
• 9 years agoHelpfull: Yes(3) No(1)
• 170..
  3x+4x/2+10x/10=102
  x=17
  10x=170
  
• 9 years agoHelpfull: Yes(0) No(11)
• 1st color 6 rows with white color. then color last 2 remaining rows in 2*2 manner thrice. Then you will end up in only one black square in the board.
• 9 years agoHelpfull: Yes(0) No(2)
• paint the rows and 2*2 squres to get a black square...
• 9 years agoHelpfull: Yes(0) No(1)
• paint 1st,2nd,3rd,4th,6th,7th,8th rows and 1st,2nd,3rd,6th,7th,8th columns with white....
• 9 years agoHelpfull: Yes(0) No(0)
• repaint 1st,2nd,3rd,6th,7th,8th columns and 1st,2nd,3rd,4th,6th,7th,8th rows as white...now we will get single black square....!!!
• 9 years agoHelpfull: Yes(0) No(0)
• a) by repainting squares of a row
  note: when we repaint black =>white an vice-versa
  if first square (r1,c1) chess is white then repaint 1,3,5,7 rows
  now we will get 1,3,5,7, columns in black and rest in white color
  now paint 2,4,6,8 columns
  done we have 8X8 black color chess
  
  b) by repainting 2X2 squares
  yes, we can get one 8X8 big square
  (only those who can understand read else ignore the process)
  but to understand please use an excel sheet with and fill 0 & 1 alternately in 8 rows and columns and try this where 0 is white and 1 is black and first square is 0(white)
  when we apply change 1=>0 and 0=>1
  >change(repaint) a1to b2 (includes a2,b1 also)
  >change b1 to c2, e1 to f2, f1 to g2 => observe that first row is all 1(black squares row)
  >change a2 to b3, c2 to d3, e2 to f3, g2 to h3 => 2nd row all 1
  >change b3 to c4, c3 to d4, f3 to g4, g3 to h4 =>3,4 row completed
  > now repeat above 4 steps on remaining square
  (since same pattern repeats) and will get all squares painted same color... :)
• 9 years agoHelpfull: Yes(0) No(0)
• I am drawing two chess boards here one is simple and another is repainted...
  
  Simple Repainted
  A B C D E F G H
  1. |#|_|#|_|#|_|#|_| |#|#|#|_|#|_|#|_|
  2. |_|#|_|#|_|#|_|#| |#|#|#|#|_|#|_|#|
  3. |#|_|#|_|#|_|#|_| |#|#|#|_|#|_|#|_|
  4. |_|#|_|#|_|#|_|#| |_|#|_|#|_|#|_|#|
  5. |#|_|#|_|#|_|#|_| |#|_|#|_|#|_|#|_|
  6. |_|#|_|#|_|#|_|#| |_|#|_|#|_|#|_|#|
  7. |#|_|#|_|#|_|#|_| |#|_|#|_|#|_|#|_|
  8. |_|#|_|#|_|#|_|#| |_|#|_|_|#|_|#|_|
  
  
  I painted row 2A-1B and
  2X2 Square 3B3C-2B2C.
• 9 years agoHelpfull: Yes(0) No(0)
• I am drawing two chess boards here one is simple and another is repainted...
  
  Simple ..........................................Repainted
  ...... A..B..C..D..E..F..G..H
  1. |#|_|#|_|#|_|#|_|.............|#|#|#|_|#|_|#|_|
  2. |_|#|_|#|_|#|_|#|.............|#|#|#|#|_|#|_|#|
  3. |#|_|#|_|#|_|#|_|.............|#|#|#|_|#|_|#|_|
  4. |_|#|_|#|_|#|_|#|.............|_|#|_|#|_|#|_|#|
  5. |#|_|#|_|#|_|#|_|.............|#|_|#|_|#|_|#|_|
  6. |_|#|_|#|_|#|_|#|.............|_|#|_|#|_|#|_|#|
  7. |#|_|#|_|#|_|#|_|.............|#|_|#|_|#|_|#|_|
  8. |_|#|_|#|_|#|_|#|.............|_|#|_|_|#|_|#|_|
  
  
  I painted row 2A-1B and
  2X2 Square 3B3C-2B2C.
  
• 9 years agoHelpfull: Yes(0) No(1)
• 1) Repaint each second column (4 steps were there)
  2) Repaint each white row (also have 4 steps)
• 4 years agoHelpfull: Yes(0) No(0)