i know NPV=0.735 - but how do they get to that answer?

219. You are in a two-period world where a risk-free and risky asset are traded, see the figure below for the prices and payoffs. You have a project that costs 10 at time zero and pays 12 in the up and then up state, 10 in the up and then down state, 12 in the down and then up state, and 10 in the down and then down state. What is the NPV of this project