निम्नलिखित कथनों की परीक्षा कीजिए :
- 1.सभी रंग सुखद हैं।
- 2.कुछ रंग सुखद हैं।
- 3.कोई भी रंग सुखद नहीं है।
- 4.कुछ रंग सुखद नहीं हैं।
यदि कथन 4 सत्य है, तो निश्चित रूप से क्या निष्कर्ष निकाला जा सकता है?
Read this question in English
Examine the following statements:
1. All colours are pleasant.
2. Some colours are pleasant.
3. No colour is pleasant.
4. Some colours are not pleasant.
Given that statement 4 is true, what can be definitely concluded?
(a) 1 and 2 are true. · (b) 3 is true. · (c) 2 is false. · (d) 1 is false.
उत्तर और व्याख्या · explanation in English
Answer: (d) 1 असत्य है।
'Some colours are not pleasant' is the exact contradictory of 'All colours are pleasant', so if statement 4 is true, statement 1 must be false. Statements 2 and 3 could go either way.
- Statement 4 (some colours are not pleasant) and statement 1 (all colours are pleasant) are contradictories: exactly one of them is true.
- 4 is true, so 1 is false — definitely.
- Statement 2 may or may not hold, because the remaining colours may or may not be pleasant; so 2 and 3 are both undetermined.
- Only (d) is certain.
- ✗ (a) 1 is false, so '1 and 2 are true' cannot hold.
- ✗ (b) 4 does not rule out some colours being pleasant, so 3 is not certain.
- ✗ (c) 2 may still be true — some colours can be pleasant while others are not.
- ✓ (d) 'Some … are not' is the contradictory of 'All … are'; when one is true, the other is false.
Remember · Contradictory pairs: All vs Some-not, and No vs Some. If one of a pair is true, the other is false; other pairs stay undetermined.
Question and answer: UPSC's official GS Paper II (2017, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·