Question 1125350
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            Mental solution is possible.



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We need to find a decomposition of the number 270 into the product of two positive integer numbers that differ by 3.


In addition, these factors should be close enough to  {{{sqrt(270)}}}, which is about 17.


Having these two hints, it is the matter of seconds to find the decomposition


    270 = 15*18.


<U>Answer</U>.  The number of rows is 15.
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