Cron commands

Hi all,

I've got cron working running every 30 mins like so:

*/30 * * * * php /blah/blah/script.php

But how would I set it to run at 15 mins past the hour (so 12:15, 13:15, 14:15 etc...)

Actually have 4 scripts that I need to

- 1st one run on the hour
- 2nd one run 10 past the hour
- 3rd one run 20 past the hour
- 4th one run 30 past the hour

Thanks for the help