Question 959293
A positive integer has three digits. The product of the digits is 135. 
What is the sum of the digits
<pre>

Break 135 into a product of primes:

135 = 3*3*3*5

That's a product of four digits, not three. To reduce it to three,
we'll have to multiply two of them together and take their product
as a digit.  The only way to multiply two of those together to get 
a single digit is to multiply two of the 3's together as having a 
factor of 9.  That is, the digits have to be 3,5, and 9.  So the 
sum of the digits is 3+5+9 = 17.

Edwin</pre>