Question 1108326
.
<pre>
1.  The set of five-digit numbers that are NOT divisible by every element of (1,2,3,4,5,6) is the same as 
    the set of five-digit numbers that are NOT divisible by every element of (2,3,5).



2.  The probability that a five-digit number chosen at random, one at a time is NOT divisible by every element of (2,3,5) is 

    P = 1 - {{{1/2}}} - {{{1/3}}} - {{{1/5}}} + {{{1/(2*3)}}} + {{{1/(2*5)}}} + {{{1/(3*5)}}} - {{{1/(2*3*5)}}} = 0.267  (approximately).


Use Venn diagram.
</pre>