Quantitative Aptitude • Number System & SimplificationEasy
Simplify: (40² − 32²) ÷ (40 − 32)
A. 72✓ Correct Answer
B. 8
C. 1,280
D. 144
💡 Solution & Explanation
Use the identity a² − b² = (a + b)(a − b). So (40² − 32²) ÷ (40 − 32) = (40 + 32)(40 − 32) ÷ (40 − 32) = 40 + 32 = 72. This saves squaring 40 and 32: 1600 − 1024 = 576, and 576 ÷ 8 = 72 gives the same answer.