Susan made a block with small cubes of 8 cubic cm volume to make a block ,3 small cubes long, 9 small cubes wide and 5 small cubes deep. She realizes that she has used more small cubes than she really needed. She realized that she could have glued a fewer number of cubes together to lock like a block with same dimensions, if it were made hollow. What is the minimum number of cubes that she needs to make the block?
option
a) 114
b) 135
c) 21
d) 71

• Answer is 114
  Dimensions of big cube = 6 x 18 x 10
  dimensions of small cube = 2 x 2 x 2
  Dimensions of cube leaving the outer layer of large cube (which forms the outer layer of hollow cube) = 2 x 14 x 6
  No. of small cubes for hollow cube = 6*18*10/8 - 2*14*6/8 = 114
• 13 years agoHelpfull: Yes(43) No(16)
• 114
• 13 years agoHelpfull: Yes(5) No(14)