61 small identical cubes are used to form a large cube. How many more cubes are needed to add one top layer of small cube all over the surface of the large cube ? Choose the correct option:
A) 64 B) 128 C) 152 D) 155 E) 256
61 small cube will make a large cube with 4 cubes in each line i.e.   Adding one layer will require one cube at each end and hence new cube will have 6 cubes in each line.   Total number of small cubes in new cube = 6^3 = 216   Extra cube required = 216 - 61= 
<gadget id="calculator">216 - 61</gadget>
<output>155</output>
155   Hence, 155 is the answer.
<result>D</result>
61 small identical cubes are used to form a large cube. How many more cubes are needed to add one top layer of small cube all over the surface of the large cube ?