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Using the identity (n+1)² − n² = (n+1) + n, the value of 16² − 15² is:
A{'text': '29'}
B{'text': '30'}
C{'text': '31'}
D{'text': '32'}
Answer & Solution
Correct answer: C. {'text': '31'}
1. The identity (n+1)² − n² = (n+1) + n holds for any natural number n.
2. Here n = 15, so 16² − 15² = 16 + 15 = 31.
3. Verification: 16² = 256, 15² = 225, 256 − 225 = 31 ✓.
4. Hence the answer is **31**.
_Source: Selina Concise ICSE Class 8 Mathematics Ch 3 "Squares and Square Roots", Properties of square numbers (difference)_
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