JEE Mains · Maths · STD 11 - 6. permutation and combination
All the arrangements, with or without meaning, of the word \(FARMER\) are written excluding any word that has two \(\mathrm{R}\) appearing together. The arrangements are listed serially in the alphabetic order as in the English dictionary. Then the serial number of the word \(FARMER\) in this list is .... .
- A \(75\)
- B \(77\)
- C \(76\)
- D \(80\)
Answer & Solution
Correct Answer
(B) \(77\)
Step-by-step Solution
Detailed explanation
\(FARMER \,(6)\) \(\mathrm{A}, \mathrm{E}, \mathrm{F}, \mathrm{M}, \mathrm{R}, \mathrm{R}\) \(A\) \(E\) \(F\) \(A\) \(E\) \(F\) \(A\) \(M\) \(F\) \(A\) \(R\) \(E\) \(F\) \(A\) \(R\) \(M\) \(E\) \(R\) \(\frac{\lfloor 5}{\lfloor 2}-\lfloor 4=60-24=36\)…
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