here uis how you should do the quest.

NERICON'S GARDEN

Quest: Philosophy of life
Solution: You will meet three philosophers on the southern road to Nericon's Garden. They are followers of Nemris, the philosopher, and unable to worship the statue of their master in Nericon's Garden because the gate is locked. They will give you a book and ask you to retrieve the key from a merchant named Blake in Rivertown. Just go and get the key.

Quest: Nericon's garden
Solution: (See quest above) - This quest is added to your journal after you've bought the key to Nericon's Garden from the merchant Blake in Rivertown. He tells you there is a myth about a treasure being hidden in Nericon's Garden. He also mentions something about frogs...
Enter Nericon's garden with the key from Blake. Take a few minutes to read the book the followers of Nemris gave you. Then approach the statue and answer the questions. You will only get one chance to answer the questions correctly so save or make sure you've really carefully read the book <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" /> . If you have given the correct answers you will be awarded one skill point in 'Restoration'.
Time to investigate on the frog and treasure part of the story. There is a lake in the center of the garden and there are frogs in it. There's obviously not much else to do except for killing the frogs. Do that. Kill all of them (four in total) and a portal is going to appear. It leads to the treasure.