The distances in space are measured in light-years. The distance from Earth to a star is 5.9 × 10^13 kilometers. What is the distance, in light-years, from Earth to the star (1 light-year = 9.46 × 10^12 kilometers)?
1 light year = 9.46 x 10^12 km. Therefore how many light years = 5.9 x 10^13?. Do cross multiplication you'll get. 5.9x10^13 / 9.46x10^12 = 6.23 light years. So d is the correct answer.
