Question 1005635
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A number divided by 39 leaves reminder 20. The same number divided by 13 leaves reminder ___ ?
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The first part of the condition,  "A number divided by  39  leaves reminder  20."  implies that 
our number  N  can be presented in the form


N = 39*Q + 20.


Now ask yourself,  what the remainder will be if to divide  39*Q + 20  by  13?


Clearly,  the remainder will be the same as if you divide  20  by  13,  i.e.  7. 

Because 39 is multiple of 13.


<U>Answer</U>. &nbsp;The same number divided by &nbsp;13 &nbsp;leaves reminder &nbsp;7.