SOLUTION: A large cube is dipped into red paint and divided into 216 smaller congruent cubes. one of the smaller cube is then randomly selected. What is the probability that the cube selecte

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: A large cube is dipped into red paint and divided into 216 smaller congruent cubes. one of the smaller cube is then randomly selected. What is the probability that the cube selecte      Log On


   

Question 370267: A large cube is dipped into red paint and divided into 216 smaller congruent cubes. one of the smaller cube is then randomly selected. What is the probability that the cube selected will have at least 25% of its surface area painted red?
express answers as a common fraction
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
The surface are of a cube with sides of 3 = 6*3^2 = 54, so after the division, 54 of the cubes will have some paint on them.
The center cube of each face will have only one of its faces painted, 6 of those, so 48 cubes will have 2 or 3 faces painted, giving them more than 25% coverage.
48/216 = 2/9