What is the chance of flush on flush with a single opponent?
And hitting the flush?
Both player have suited hole cards (same suite).
Your chance of a suited hole cards is 12 / 51 = 0.235
Just short of 1/4
combin(11,2) / combin(50,2) = 0.045 = 1 / 22
Chance you (both) make a flush by the river = 0.0393 = 25 : 1
This includes 4 and 5 on the board so another player with with a single flush could win.
If they play any two flush then like 2.0% but they are not likely to play like QJT little or under T and not connected so like 1.5%.
Let's say one card and T or greater
You are playing 89s
Opponent chance = 5*39/50 = 0.16
That is random
If your opponent is only playing A-T then 0.40 chance they have single flush (higher than you).
Well pair are also in their range - but then they can make a boat to beat your flush so that is about a wash.
Make flush with the board only showing 3
You are safe as there cannot be an over flush
0.044 = 21.63 : 1
That number make sense as they say suited adds about 4%.
What are the chances of a 4 or 5 flush on the board
0.0048 = 207 : 1
You are in a situation of getting beat by a single card
Not going to face 4 or 5 flush on the board often but if you do be cautions - there is about a 40% chance you are beat if you range your opponent to A-T. Bet hard when the board hits 3.