Excel Formula for calculating what to bet???

So I want to create an excel formula for what I would have to bet to win that amount.  For example, If I want to win $25.00.  I want to put in what the line is and have it spit out what I would have to bet.  Anyone have any idea how to do that?

for real?

sorry.  =[refer to your line amount/100]*25 for dogs

=25/[refer to your line amount/100] for chalk

Props Dutch,

Not everyone knows that formula. Thx