Answer: 2.84*10^13 km
To answer this question, you need to convert the year into second as the velocity of the light using meter/second unit, then convert the meter into kilometers. Since light travel 1 meter in 1/299,772,458 second, then the light velocity should be 299,772,458m/s. The calculation would be:
Distance traveled= velocity * time
Distance traveled= 299,772,458m/s * 3 years * 365.25 days/year * 24 hours/day *3600 seconds/ hour= 2.84 * 10^16 meter * 1km/1000m= 2.84*10^13 km