"Consider an auction, with reserve price $X$ chosen from distribution $G$ where the item is allocated to a uniformly chosen random bidder among those who bid above the reserve price. The winner pays $X$, the reserve. Show that this auction is truthful, that is that the optimal strategy is to bid your value."
I just need a little direction to get started, I'm wondering how to show that bidding value $V$ is indeed the optimal strategy in an auction like this.