Think You're Smarter Than a Second-Grader?

Back when I was applying to law school, lo those many years ago, the LSAT had a bunch of those "if Betty can't sit next to Carl, Bill must sit at the head, and Carl must sit adjacent to Sue, who does the dishes after dinner?" problems.
I hated those problems. Hate, hate, hated them. Fortunately, that "logic" section only counted 25% towards my final score. Now? I think it's nearly half of the exam. Today, I would never get into law school. Not in a million years.
And it appears I've passed down my logic deficiency to Mr. M.
This afternoon, we spent nearly an hour laboriously coloring in a "math" car. Fun times, my friends. Fortunately, little logic was involved (and now I see why Mr. M doesn't give a whit about staying in the lines -- fine motor skills be damned).
The taxing logic challenge came later. From his backpack he withdrew an insidious "Multiplication and Division" packet that he'd finished at school. The teacher wanted me to sign underneath his mediocre grade and send it back to her.
Being a lawyer, I try not to sign things until I've read and understand them. So I scanned the problems Mr. M got wrong, and most of the time I could see why.
Until . . . this one:
Jeff and his brother Jack run laps at the track. Jeff is 4 years older than his brother, so he runs faster. Jeff runs 4 laps every time Jack runs 3 laps. How many laps will Jeff have to run when Jack has run 18 laps?
A grid followed the problem -- here's my best effort to snap it:

Mr. M's answer -- 19 -- made sense to me. If Jack runs 3, Jeff runs 4. If Jack runs 4, Jeff runs 5. Why not? But, as you can see, that answer was a big purple wrong.
Tell no one, but umm, I've been sitting here for the last hour trying to figure this out. It's driving me crazy. After a lot of head scratching, my final answer is 24.
So help me, people. Help me.
Was this hard for anyone else? A tad difficult? Anyone? Anyone at all? Hello?
What is wrong with me?
Thank God it's (almost) summer, is all I can say.
TGIS.

Labels: Logic Deficiency, Second-Grade Math, Tgis