Quote Originally Posted by Thunder
And if this is true then 10/25 (or 1/2.5) equals 1.5:1 and not 2.5:1.
The bold is where you're fucking up and explains your confusion.

Quote Originally Posted by spoonitnow
Suppose we have AK on A897K in position against a range of {88-99, JT, AQ-AJ}, and Villain bets $10 into a pot of $15, can we call profitably? Note: She can also figure out that raising is -EV there but that's beside the point.
The fraction 10/25 would assume we were calling 10 to win 15, but we're really calling 10 to win 25. After Villain bets 10 into a pot of 15, the pot is 25 with us calling 10. This gives us 2.5:1 pot odds which equals 1/3.5, etc.