Ramon and his stupid sweater (pg 88 of LR book)

[chrismcmanus10]

The part where the assumption is that Ramon has at least $20 in his wallet makes no sense to me. If I don't negate the assumption, he doesn't have enough to buy the sweater because having at least $20 isn't sufficient. Doesn't he need at least $40 to buy the sweater? What am I missing??

[tommywallach]

Yes, but if he can afford the sweater, he has at least $20 (in fact, we know he'd have more). See how that works? We also know he has more than $10 and more than $0.

-t