12. The letters of the word FLOWER are taken 4 at
time and arranged in all possible ways. The number
of arrangements that contain the letter 'F' is 240 at
which do not contain Fis---
Answers
Answered by
2
Answer:
12
Step-by-step explanation:
Since F and R occupy first and the last position, we can select any two letters out of the remaining four.
These can be done in
4
C
2
ways
i.e.
n
C
r
=
(n−r)!r!
n!
=
(4−2)!2!
4!
=
2!2!
4!
=
2!2!
4×3×2×1
=6
These 2 selected letters can be arranged themselves in 2 ways.
Total number of ways =6×2=12
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