UPSC Prelims 2024 CSAT Paper II · Q5 of 79 Mental Ability medium

What is the least possible number of cuts required to cut a cube into 64 identical pieces?

  1. (a) 8
  2. (b) 9 ✓ UPSC's answer
  3. (c) 12
  4. (d) 16

Why the answer is (b)

• 64 = 4 x 4 x 4, so the cube is divided into 4 equal parts along length, 4 along breadth, and 4 along height.

• Dividing one edge into 4 equal parts requires 3 straight cuts.

• The same 3 cuts are needed in each of the three mutually perpendicular directions.

• Total cuts = 3 + 3 + 3 = 9, so option (b) follows.

Why the other options are wrong

(a) 8
8 cuts cannot provide 3 cuts in each of the three dimensions needed for a 4 x 4 x 4 division.
(c) 12
12 cuts are more than the 9 cuts needed for 3 cuts in each of the three dimensions.
(d) 16
16 cuts are more than the 9 cuts needed for 3 cuts in each of the three dimensions.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2024, held on 16 June 2024. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

Reading the answer is not the same as getting it right under a clock. Practise this question with UPSC's negative marking, and anything you miss goes into an error notebook until you get it right twice.

Practise this paper free