It's best to attempt this trophy as early as possible because if you do this after finishing the main game you will struggle to beat your times consistently.
Also do this on an event as early in the game as possible because using a second PSN account on your console will mean you'll have to play through the game on your second account up until that event so if you use an early event then this saves some time.
Ok so you should have an event on your main account that you haven't played that's either a hot lap event or a race. Overtake events are not ideal for this but will do the job if no other event is possible.
Race this event on your main account and make sure you get a poor as possible time on it, about 1-2 mins of resting before the finish line before actually finishing.
Finish the event and press X until you are back to the events menu, remember the time you got in the event as you are going to be beating this with your alternative account.
Return to the XMB and sign in to your alternative account and start up the game again.
Start up the same event you just did and beat the time by a few seconds, when you finish the event press Triangle to upload the time to PSN and challenge your main account.
Now sign back into your main account on the XMB and start up the game.
Go to the Pitwall and the challenge from your alternative account will appear, press X and select the message and press X on Game Data.
You will automatically be challenging this time now, all you have to do is beat the time and as long as you do not delete the challenge message you can keep redoing the challenge and this will count towards your 10 times beating towards the Trophy.
All you have to do is beat the time set by your alternative account all 10 times and you will get the Trophy.
You will also get this trophy the first time you beat your alternative account
The Ghost Busted trophy in MotorStorm RC worth 21 pointsBeat a friend's ghost in a Race or Hot Lap event who currently sits above you in the leaderboards.