At 4:00 pm, George, who is at the origin of the $(x,y)$ coordinate system, sends out a flash of light. Gracie is located at position $(5,12)$, where the units on the axes are light-minutes. As Gracie awaits the flash, she calculates the time at which she should set her clock to ensure that the usual clock synchronization procedure will be successful. What's the answer?

At 12 noon, George—who is at the origin of the ($x$,$y$) coordinate system—sends out a flash of light. Gracie is located at position (15,8), where the units on the axes are light-minutes. As Gracie awaits the flash, she calculates the time at which she should set her clock to ensure that the usual clock synchronization procedure will be successful. What's the answer?