Quantitative Aptitude • Number System & SimplificationEasy
Simplify: (25² − 15²) ÷ (25 − 15)
A. 10
B. 80
C. 375
D. 40✓ Correct Answer
💡 Solution & Explanation
Use the identity a² − b² = (a + b)(a − b). So (25² − 15²) ÷ (25 − 15) = (25 + 15)(25 − 15) ÷ (25 − 15) = 25 + 15 = 40. This saves squaring 25 and 15: 625 − 225 = 400, and 400 ÷ 10 = 40 gives the same answer.
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