Multiple operation in c#

Question

 I' m trying to Multiple this Equation in C#

 

331612320 * 2.279 = 755744491.8 

ans is  755744491.8

But in excel it gives me 

 

 331612320 * 2.279 = 755744477.3

 

ans is  755744477.3

 

difference :

-14.54750705

 

how will  i get excel answer   in c# ?

Thanks in advanced