Poker odds and probability?

[jhonrtin]

Poker prob problems/?
After the turn (4th card on the board) find the odds of each, and the size the pot must be to
make a call of a $20 bet.
1. You have a four flush. What is your odds of making your flush?
2. You have two pair. What are the odds of making a full house?
3. You have three of a kind. What are the odds of making a full house or better?

[Martini]

If you do a Google search for the terms "poker outs" you will find all the information you need to properly calculate odds.

[Wedge Rock]

1. 8 outs x 2.2 = 17.6%
2. 4 outs x 2.2 = 8.8%
3. 9 out x 2.2 = 19.8% to the full house.  Add an extra out for the quads, so 10 outs x 2.2 = 22%

[BigPair88]

I learned a quick and easy way to calculate outs your approximate outs on the turn and the river.

After the flop, count your number of outs and multiply by 4.
After the turn, count your number of outs and multiply by 2.
This should bring you to within 1 or 2 percent of your precise percentage.

So, for your scenarios, after the turn
1- 9 outs to make your flush ( 9X2=18) 18%-ish (prob more like 19% or 20% to be precise)
So you would want to be getting about 5 to 1 to call.

2- 4 outs to make your full house ( 4X2=8) 8%-ish ( prob more like 9% or 10%)
So you would want to be getting about 10 to 1 to call

3- 6 outs to make your full house (6X2=12) 12%-ish (prob more like 13% or 14%)
So you would want to be getting 8 or 9 to 1 to call
   7 outs to include making quads (7X2=14) 14%-ish (prob more like 15% or 16%)
So you would want to be getting 6 or 7 to 1 to call.

Again, keep in mind that this simple math for quick calculations, not exact calculations

[Wedge Rock]

I learned a quick and easy way to calculate outs your approximate outs on the turn and the river.

After the flop, count your number of outs and multiply by 4.
After the turn, count your number of outs and multiply by 2.
This should bring you to within 1 or 2 percent of your precise percentage.

I agree, except that I multiply by 2.2 for the river, as described above.

3- 6 outs to make your full house (6X2=12) 12%-ish (prob more like 13% or 14%)
So you would want to be getting 8 or 9 to 1 to call
   7 outs to include making quads (7X2=14) 14%-ish (prob more like 15% or 16%)
So you would want to be getting 6 or 7 to 1 to call.

I disagree with your calculation of the number of outs.  Look at the OP.

3. You have three of a kind. What are the odds of making a full house or better?

It doesn't matter if you have a pair in your hand, or if the board pairs, of the 6 known cards (the board (flop + turn) and your hole cards) there is three like-kind cards and three non-paired cards.

X X X A B C

Your outs to make a full house is getting one of the other cards (A, B, or C) to pair.  There are three other A's, three other B's and three other C's (assuming that a burn card wasn't exposed removing one of your outs).  So you have 9 outs to the full house, not six.  And of course, the question asks your odds for a full house or better, so you have to consider the 4th X for quads.  So that's 10 outs total, not 7.

10 x 2.2% = 22% to make a boat or better.

[Killingbird]

the 2/4 tick is not perfect, but its a good quick method for when playing live.

[Martini]

the 2/4 tick is not perfect, but its a good quick method for when playing live.

I would never change my play based on the discrepancy between the estimate and the actual percentage.