The interstellar cruise ship races through a Martian spaceport. According to galactic regulations, the safety strobe lights on the ship's bridge are assumed to blink every 1.50 seconds. A rookie policemartian, based on the planet, issues a ticket, claiming he measured the time interval among blinks as 1.81 seconds. You are called on by the indignant captain to describe the discrepancy, who maintains that her lights are totally compliant with code. What spacecraft speed will exhibit both the captain and policemartian to be correct?