Hello there,
This is Rod here.
The Oracle Database 12c: Data Guard Administration 1Z0-066 exam is difficult and
the Oracle Database 12c: RAC and Grid Infrastructure Administration 1Z0-068 exam is no joke.
The majority of the questions has multiple answers and a few questions are not perfectly written.
You should use these practice tests to get really prepared for the exam and clear it.
If you have any questions don't hesitate to contact me.
Wish you the best of luck.
Rod.