After seeing it here last week, I showed it to my 3rd and 4th grade sons and we/they had fun talking about it and thinking about how to solve it, but they did not figure it out. I bet when I get home from work today, my 3rd grader will have showed some of his friends and will tell me about what they did/thought ...then go outside and shoot some hoops in the driveway
In any case, I think that teaching critical thinking processes for how to attack a problem is very important no matter what you end up doing in life ...but maybe that's why I'm a BSME engineer. If you can't think that way, you can always flip burgers, or now adays, work the register since you don't even have to know how to add or subtract to do that anymore.