Good luck fella, here's a few tips.
As sycamore says, if you get the chance sketch a few things down (diagrams/numbers). It really helps.
The old "two ac leave and are heading towards each other etc". Forget the two different speeds, work out a closing speed.
eg A = 240 kts B =120kts in opposite directions. Closing speed 360 kts. You can then work with one stationary and one at 360kts (6 miles a minute, get used to that).
Also don't be afraid to do things arse about face. If the question asks for distance and a time, you can work out the time first and extrapolate the distance from that, its sometimes easier.
The answer is 0225 and 580nm btw see above.