Question 1141831
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First, I checked that the given sequence P(0), P(1), P(2), P(3), P(4), P(5), P(6), P(7) of 8 terms monotonically increases 
and that the sum of all 8 (eight) given probabilities in the post is equal to 1 :


    0.001 + 0.006 + 0.022 + 0.052 + 0.091+ 0.128 + 0.149 + 0.551 = 1,


so the given data makes sense.



Second, the answer to the question is the difference


    P(the number of phone calls is from 2 to 6 inclusive) = P(6) - P(0) - P(1) = 


       = the 7-th term of the sequence MINUS the 1-st term and MINUS the 2-nd term  = 

       = 0.149 - 0.001 - 0.006 = 0.142.     <U>ANSWER</U>
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