The size of the track can be found by, $\displaystyle 2(7)\frac{22}{7}=2(22)=44$, and we know that if we chop this in half we'll know how far apart they are (22), and then we can forget about the circle because it no longer plays a part in the problem. Speed is speed.

O.K. Now we've gotta find at what time these two will meet. This is easy:

How much faster is the one train going than the other?

$\displaystyle 22-18=2$.

How long do you gotta ride at 2m/h before you go 22miles?

distance=rate*time, so

$\displaystyle 2t=22\Longleftrightarrow{t=\frac{22}{2}}\Longleftr ightarrow{t=11}$

Add 11 to 9 and waddayah git?

That'll be army time though...........