Odds calculation Q&A

Q: I'm trying to see if this makes sense:
You have AK. Flop is 852r. Opponent has JJ. You know this for sure.

There is $7.50 in the pot. He moves all in for $2.50. (Let's assume that AK has exactly a 25% chance of winning the pot on the flop if he's all in).

I have to call $2.50 to win $10, which is 25%. So if he moves all in for $3 I should fold?

Is that correct? Really I'm just trying to see if I understand pot odds properly, more than i care about debating calling or folding for other reasons.

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A: AK V JJ with a flop that eliminates all backdoor draws, basically simplifying it to 6 outs for the AK to win with the Jacks having 2 more jacks to eliminate any chance for the AK. I always use 45 as the range, so x/45 is the probability of hitting an out on each forthcoming street. Since you have 2 streets the chance to hit 6 outs is 6/45 + 6/44= 26.97% , given that you dont hit one the first street. There is the chance that they can hit a Jack and those odds are either 2/45 on the turn and 2/44 on the river, which only really matters if the AK were to hit on the turn since it doesnt affect anything really until AK improves.

This is how I would break it down:
-26.97 of the time AK improves and wins
-4.44% of the time a Jack will come on the turn and seal the deal so that the river doesnt affect anything if AK improves 13.63% of the time on the river
-Which breaks down in numbers to 6/44-2/45(6/44)= 13.02%
-4.54% of the time a Jack will come on the river if AK improves on the turn.
-Which breaks down in numbers to 6/45-2/44(6/45)= 12.73%
-Since you have 2 streets, each with outs on probability, you add the 2 chances together and come to a 25.75% chance of winning after a complete no drawing flop comes, of course in real simple terms, with real simple math and with no real other factors or variables in a perfect scenario, which cant be accomplished obviously.

The numbers most poker calculators gives is around 24%, slightly less than 3/1. Remember calling 2.50 to get 10 is actually 4/1, I think that may be where people get confused. So even calling 3 would be 3 for 10.50 or 3.5/1 to call, in either case making it mathematically correct to call.

I think my math is right, I don't have my Barry Greenstein book "Ace on the River" to reference my math against but oh well...