Question 2620
 Let x be one of them,another is 50-x,

 their product f(x) = x(50-x) = -(x^2-50x+(50/2)^2) +625 
  = 625 -(x-25)^2  [Use complete square]
 Since -(x-25)^2 <=0, f(x) <= 625.
 when x = 25, f(x) has max value 625.

 Thus, when the two numbers are 25, 25(in fact equal), their
 procudt is max(vale 625).

 Kenny