Yes, the questions on the show are actually not difficult. I daresay most college graduates or even non college grads with proper memory who paid attention in school can easily answer most questions. Although the questions seemingly do ramp up in difficulty as the show goes on, it never actually gets hard enough to be worth competing for a large prize for adults.
The whole smarter than a fifth grader thing is so pointless. You've got people who haven't been in the fifth grade for a long time going up against fifth graders. The average person forgets most of the stuff they learned in school because most of it isn't relevant to their day to day lives. It's not really a measure of intelligence it's how well you retain information.
While it is an entertaining show with questions that seem easy, you have to remember that for the contestants, fifth grade was many years ago, and the information in the questions is often merely fun facts and trivia. The fifth graders are able to answer these questions with ease because it is fresh in their minds and relevant to what they are currently learning.
No, I could not answer most of the questions. Without a doubt, questions on "Are You Smarter Than a 5th Grader" are very challenging and above the 5th grade level. As someone who has been through the 5th grade, I can't recall ever learning material relating to most of the questions I see on that show.