Lets set the two numbers as 'a' and 'b'
Now let us set up some equations based on the information:
- sum of two numbers 49 --> a + b = 49
- difference of the two numbers is 15 --> a -b =15
Equations
 a + b = 49 -- equation 1
 a - b = 15 -- equation 2
Solve:
 (equation 1) + (equation 2)
 2a = 64
 a = 32 -- equation 3
 (equation 3)'s value of a into (equation 2)
 32 - b = 15
 b = 17
The products of 'a' and 'b' is 544
Hope that helps!