How many times can I attempt to guess the pin code of the restrictions settings on iPad?
If you are talking about Parental Control type of restrictions on the iPad, I believe that to be entirely iOS software level. You have 6 attempts before it locks you out for a minute. It then increases the locked-out time after further failed attempts. Since you have two failed attempts, it should let you have four more without consequence, which, if one goes through, all is well, if not, you will be locked out, before you can do a 7th attempt for 1 minute - to start with.

If you fail the 7th time, it will increase the time to 5 minutes.
The eight time increases it to 15 minutes.
And if you fail the ninth time, the timer increases to sixty minutes and will be that amount until you enter the right one.