find the no. of 6 letter words that can be formed using letters of the word SQUARE such that
1.U and A always appear together.
2. U, A and R appear together.
Must it be "UA", or is "AU" acceptable as well ???
The same for "UAR", or are other perumations allowed such as "AUR", "RUA"......etc.??
1.
Consider "UA" to be a single entity
Can put these in any one of 5 positions 12, 23, 34, 45, 56
And for each of these, there are 4! ways to arrange the other letters
But....we can also write UA as AU
So.....the number of total "words" is
2 ways to arrange UA x 5 positons x 4! arrangements of the other letters
2 x 5 x 4! =
2 x 5 x 24 =
240 "words"
2.
Similarly, for UAR, consider this as a single entity
It can appear in 4 different positions 123 234 345 456
And for each of these, the other letters can be arranged in 3! ways
But....UAR can also be arranged in 3! ways
So....the total possible "words" =
4 x 3! x 3! =
4 x 6 x 6 =
144 "words"
CPhill i have no idea about it!?
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Can put these in any one of 5 positions 12, 23, 34, 45, 56
And for each of these, there are 4! ways to arrange the other letters
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what do you mean byt he first line?i thought there were 5! ways to arrange them???
can you pls make it a little simple....i really cant see the permutations in them....its too confusing!Thanks!