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While calculating the value of 95 × 103, a student writes 95 × 103 = 10000 + 10a - 15.
Then, what is the value of a ?
Correct Answer: C — -20
Explanation:
Given: While calculating the value of 95 × 103, a student writes 95 × 103 = 10000 + 10a - 15. Concept used: ⇒ (a - b) × (c + d) = (a × c) + (a × d) - (b × c) - (b × d) Calculation: We can write 95 × 103 = (100 - 5) × (100 + 3) ⇒ (100 ×100) + (100 × 3) - (5 × 100) - (5 × 3) ⇒ 10000 + 300 - 500 - 15 ⇒ 10000 - 200 - 15 We can write it as, ⇒ 10000 - 20 × 10 - 15 Compare with given statement, 10000 + 10a - 15. ⇒ a = - 20 ∴ Option 3 is correct.