Question

How many words formed with the letters in "COOPERATOR" begin with the two Rs?

Answer 1

Explanation:

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Answer 2

Answer:6720

'COOPERATOR' consist of 10 words, in which there are Two R's and 3 O's and C,P,E,A and T.

where if three O's kept together practically it will be involving (10-3+1)=8 following characters of 'OOO'RR'C'P'E'A'T.

Therefore such no of arrangements is (8!)(2!)=40329/2=20160

Explanation:

the number of letters begin with 2R's :

while for two R remaining 8letters where 3 O's

(8!)/(3!)*20160=6720 words are begin with two R's.