Just like me

I used to love those math problems that went like, "A train leaves Station A travelling at XX km/hr. Another train leaves Station B travelling at XX km/hr. How long before the trains collide?" (Or some such thing.)

I think Liam is a man after my own heart. The kids started swimming lessons today and I said, "Liam, your lesson starts twenty minutes before Mallory's lesson, and her lesson ends five minutes after yours. How much longer is your lesson than hers?" Without missing a beat he answered, "Fifteen!"

A chip off the old block. :)