Question

Yesterday's Solution
Daily MCQ
REFID: 24572
How many words formed with the letters in "COOPERATOR" begin with the two Rs?
6750
6720
6740
6730​

Answer 1

Answer:

6730

Explanation:

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Answer 2

Given:

Word given = COOPERATOR

To Find :

find the number of words that can be formed from COOPERATOR which starts from 2 R.

solution:

It is a problem of Permutation and  Combination.

There are 10 letters in COOPERATOR, in which there are

2 R, 3 O, 5 different letters.

according to the question, the words should start from 2R so 2R get fixed means first two position of the words are fixed by the same 2 R.

Words made by the different R s will be counted one time because they will be same.

therefore the words will be like this: R R _ _ _ _ _ _ _ _

Now we are left with 8 letters in which 3 are same,

So the number of words can be formed= 8!/3!

                                                                 =8×7×6×5×4×3!/3!

                                                                 =8×7×6×5×4

                                                                 =6720