How to hedge a bet
How do you lock in a profit on a position you already hold?
Hedging means backing the other side of a position you already hold, so the result matters less. It is the same arithmetic as an arbitrage, applied after the fact rather than looked for.
The question is always what each result pays. Stake the second leg so both outcomes return the same and you have converted an open position into a certain one; stake it lighter and you have reduced variance while keeping some upside.
Two things people get wrong. A market's worst case is not the sum of its stakes — bet both sides and one leg always returns. And the outcome you did not bet is invisible in a list built from your own slips: a three-way market where you hold two sides looks fully covered until you count the third result.