[PokrLikeItsProse]

I do not have the book with me, but I believe this is the section where you have to take the $120-for-$100 bet first before taking the second bet.

--50% of the time, you lose the first coin flip and don't get to make the second wager, so you lose $100.
--25% of the time, you win the first coin flip and lose the second, so you gain $120 from the first wager and lose $100 on the second wager for a net profit of $20.
--25% of the time, you win both, gaining $120 on the first bet and $200 on the second bet.

So the EV of taking a slightly positive wager before taking a massively positive wager that you can only take if you win the first wager is lower than if you skipped the slightly positive bet.