Question 1124990
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From the first glance,  it is clear that the given info/input is  NOT  SUFFICIENT  to solve the problem - so,  appropriate 
auxiliary assumptions should be made.  


Moreover, &nbsp;making appropriate and likelihood assumptions is the &nbsp;<U>PART of the solution</U>.



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I will assume that the random variable  X = "the number of tankers arriving at port per day"  is uniformly distributed 
with the average value of 10.


Then the minimum value of this random variable is 0, while its maximum value is 20.


Thus the total set of its values has 21 element from 0 to 20.



Then the probability that  16 or more tankers will arrive in some day is this ratio


P(X >= 16) = {{{5/21}}}     (5 values 16, 17, 18, 19 and 20 accounted), 


which is 0.2381 = 23.81% (approximately with two valid decimal places).
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