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JEE Main 20211 SeptemberEvening Shift
Exam
JEE Main
Year
2021
Date
1 September
Shift
Evening Shift
Subject
Mathematics
Chapter
Permutation and Combination

JEE Main 2021 · 1 September · Evening Shift · Mathematics · Permutation and Combination

All the arrangements, with or without meaning, of the word FARMER...

All the arrangements, with or without meaning, of the word FARMERFARMER are written excluding any word that has two RR appearing together. The arrangements are listed serially in the alphabetic order as in the English dictionary. Then the serial number of the word FARMERFARMER in this list is _____ .

Correct answer

0

Step-by-step solution

Number of such words without both RR together

= total possible words - total possible words with both RR together

Number of such words start with A=5!2!−4!=36A = \dfrac{5 !}{2 !} - 4 ! = 36

Number of such words start with E=5!2!−4!=36E = \dfrac{5 !}{2 !} - 4 ! = 36

Number of such words start with FAE=3!2!−2=1FAE = \dfrac{3 !}{2 !} - 2 = 1

Number of such words start with FAM=3!2!−2=1FAM = \dfrac{3 !}{2 !} - 2 = 1

Number of such words start with FARE=2!=2FARE = 2 ! = 2

Number of such words start with FARMER=1FARMER = 1

Total =77= 77

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