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Let X be a set of 5 elements. The number d of ordered pairs (A,B) of subsets of X such that `Anephi,Bnephi,AnnB=phi` satisfiesA. `50le dle100`B. `101le d le150`C. `151le d le200`D. `200 led` |
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Answer» Correct Answer - C `""^(5)C_(2)*2!+"^(5)C_(2)((3!)/(1!2!)xx2!)+.^(5)C_(4)[(4!)/(1!3!)xx2!+(4!)/(2!)xx(2!)/(2!)]+.^(5)C_(5)[(5!)/(1!4!)xx2!+(5!)/(2!3!)xx2!]` `10(2)+10(6)+5(8+6)+(10+20)` =20+60+70+30=180 |
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