Question 31458
THE ANSWER IS HALF OF THE SIDES ARE PAINTED. 
THE ORIGINAL CUBE IS CUT IN HALF THREE TIMES TO FORM THE 8 CUBES. 1/2X1/2X1/2=1/8
EACH CUT EXPOSES AN UNPAINTED SIDE THEREFORE THE THREE CUTS RESULT IN 3 UNPAINTED SIDES. THE REMAINING 3 SIDE ARE THE ORIGINAL PAINTED SIDES.