Quantitative Aptitude • Number System & SimplificationEasy
Simplify: (18² − 13²) ÷ (18 − 13)
A. 62
B. 234
C. 31✓ Correct Answer
D. 5
💡 Solution & Explanation
Use the identity a² − b² = (a + b)(a − b). So (18² − 13²) ÷ (18 − 13) = (18 + 13)(18 − 13) ÷ (18 − 13) = 18 + 13 = 31. This saves squaring 18 and 13: 324 − 169 = 155, and 155 ÷ 5 = 31 gives the same answer.
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