Two identical straight rods are painted in five distinct colours so that each of them gets divided into five equal parts along the length. In one of them, the portions are marked P1, P2, P3, P4 and P5 (not necessarily in that order) whereas in the other, they are marked Q1, Q2, Q3, Q4 and Q5 (not necessarily in that order). When the rods are kept parallel to each other side by side, P1 and Q3 match, P4 matches Q1 or Q2, and Q4 matches P3 or P5. If Q3 and Q5 are adjacent, which of the following is/are possible? I. Q3 is marked at the middle portion of the straight rod. II. P2 is marked at one of the extreme portions of the straight rod. Select the answer using the code given below.
- (a) I only
- (b) II only
- (c) Both I and II ✓ UPSC's answer
- (d) Neither I nor II
Why the answer is (c)
• Number the five portions 1 to 5 along the rods. Q3 sits opposite P1; P4 is opposite Q1 or Q2; Q4 is opposite P3 or P5; Q3 and Q5 are next to each other.
• I is possible. Rod Q: Q1, Q2, Q3, Q5, Q4. Rod P: P4, P2, P1, P3, P5. Then P1–Q3, P4–Q1, P5–Q4, and Q3, Q5 are adjacent, with Q3 in the middle.
• II is possible. Rod Q: Q1, Q2, Q3, Q5, Q4. Rod P: P2, P4, P1, P3, P5. Then P1–Q3, P4–Q2, P5–Q4, Q3 and Q5 are adjacent, and P2 is at an end.
• Both situations can occur: (c).
Why the other options are wrong
- (a) I only
- II is also possible (P2, P4, P1, P3, P5 against Q1, Q2, Q3, Q5, Q4).
- (b) II only
- I is also possible (Q3 can be in the middle).
- (d) Neither I nor II
- Valid arrangements exist for both I and II.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2026, held on 24 May 2026. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.