I think most people over the age of 12 have heard many riddles like this. PARENTS of 6-8 year olds get to hear these kinds of riddles MANY times, and every time, all the good parents think it over, look VERY puzzled, and then say, "I give up... What??" and they they laugh really hard and say, "That's a good one!"
When adults tell them, the best you can hope for is a "Ha-ha! <groan> Good one!"
Which would you rather have from us? (a) "We give up... that's a toughie..." or (b) "Yes, I get it... it took a while, but I got it... you're VERY clever!" or (c) "Ha-Ha! I like that one! <groan> ;-)"
Take your pick! :-)