Why, why, why?

Andy asks why about 100 times a day. I know it's normal for this age, but what gets me is when he asks a question he already knows the answer to, and doesn't agree to my answer.

"Mommy, is it afternoon?"
"Yes, Andy, it's 3 o'clock, it's afternoon."
"No it's not. It's morning."
...

I have taken to asking him the question back instead.

"Mommy, where's Daddy?"
"Where do you think he is?"
"At work."

That seems much better than him arguing with me over a question I frankly don't care the answer to. I have also tried this technique"

"Mommy, do cats have tails?"
"Yes, cats have tails."
"No they don't."
...
"Andy, if you knew the answer, why did you ask me in the first place?"
...

He's probably going to be a lawyer, isn't?