Ok, the best way to have a swing at this, is to first of all, ignore the flagpole, and deal with that part of the problem afterwards, let's first find out when they cross paths, and from there we can figure out how far each has traveled and therefore find their relative distances from the flagpole.
The runners are 6km "Left" and 5km "Right", therefore, the distance between the two is 11km, I'm not much of a fan of Km/h, so for calculations sake let's convert Km/h to M/s, this is only for me, doing the calculations in Hours and minutes is all fine, but I'm in love with metric.
9Km/h = \frac{9*1000}{60^{2}} = 2.5ms^{-1}
8Km/h = \frac{8*1000}{60^{2}} = 2.2222ms^{-1}
Now we have some metrics, for my bennefit anyway, we could use relative velocities to find out the collision time, for runner A, runner B is approaching him at his speed + runner B's speed, this is "Relative velocity", and its the same for both runners, but we only need to do the math with runner A, so let's have runner B as a stationary object and runner A moving at Runner A's speed plus Runner B's speed, to make the maths ALOT easier.
V_{a} + V_{b} = 2.5 + 2.222 = 4.722ms^{-1}
Now, we have a distance, and a speed to work with, the rest becomes somewhat self explanitory:
V_{speed} = \frac{Distance}{Time}
So:
Time = \frac{Distance}{V_{speed}}
We find that the travel time before A meets B is 2329.5 seconds (seems like a massive number, but it is, after all, equal to ~39 minutes).
Now, the analogy is, that if A and B where too meet, they would do so at the same time, A cannot collide with B and then B collides with A, its a mutual collision between the two runners, both must be travveling for ~39 minutes before they meet eachover in the run, it seems rather counter intuitive at first since the ~39 minutes is the time taken for A, moving at the relative velocity of A+B too meet B, who in this case, for maths, is stationary, but it does work out, since when you use the "Normal" velocities of both, rather then having one going "Super fast" and the other being "Stationary" you find that it does in fact take them 39 minutes to both collectively cover the 11km (A does, say 6 of those Kilometers, and B does 5)
Now that you know the time that both of them have to run before they meet eachover, I hope it will be more obvious how to figure out the distance A or B has travveled before meeting the other, and from that distance, figure out how far the collision is from the pole.
