My guestimate:  at 50% it would take 2 - 5 years 

In 2 years 3Com would make $945 million in sales.

  $1,200,000. * [(1.5)]^2 * 350.  =   $945 million sales.

In 5 years 3Com would make 

  $1,200,000. * [(1.5)]^5 * 350.  =   $3.189 billion sales

(I'm not sure how much revenue would be needed)

But, I think the Palm computer is going to grow faster
than 50% a year.  I'd say anywhere's from 3-10 times
in a year.  So the calculation goes like this:

1 year at 300% annual growth  --
     $1,200,000. * [(3.00)^1] * 350.  =   $1.26 billion sales
    
2 years at 300% annual growth --

     $1,200,000. * [(3.00)^2] * 350.  =   $3.7 billion sales