287 × 287 + 269 × 269 - 2 × 287 × 269 = ?
A. 534
B. 446
C. 354
D. 324
Answer: Option D
Solution(By Examveda Team)
$$\eqalign{ & \left( {287 \times 287 + 269 \times 269 - 2 \times 287 \times 269} \right) \cr & = {\left( {287} \right)^2} + {\left( {269} \right)^2} - \left( {2 \times 287 \times 269} \right) \cr & = {\left( {287 - 269} \right)^2} \cr & = {\left( {18} \right)^2} \cr & = 324 \cr} $$[∵ a2 + b2 - 2ab = (a - b)2 ]
Related Questions on Number System
Three numbers are in ratio 1 : 2 : 3 and HCF is 12. The numbers are:
A. 12, 24, 36
B. 11, 22, 33
C. 12, 24, 32
D. 5, 10, 15
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