CAT
Exam
How many words are there in which letters of the word RAINBOW be arranged so that the vowels are never together?
Read Solution (Total 4)
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- Total alphabets are 7
so they can be arranged in 7!
now consider all the vowels in one unit..so 4+1=5
they nw can be arranged in 5!3!..
this is the case when all vowels are together which is not allowed..
so total arrangements are=7!-5!3!=4320 - 11 years agoHelpfull: Yes(3) No(2)
- 7!-5!*3!=4320
- 11 years agoHelpfull: Yes(2) No(1)
- using permutations
for all combinations = 7p7
for 3 vovels together= 5p3
for 2 vovels together= 6p2
7p7- 5p3 - 6p2
by solving .....
=5040-60-30
=4950 - 11 years agoHelpfull: Yes(0) No(1)
- _C_C_C_C_
5 places are available for vowels.
So, 4! * 5C3 * 3! = 1440 - 4 Months agoHelpfull: Yes(0) No(0)
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