time = distance/speed, as you surely know. About the scientific notation, you just need to express the result as a number with one digit and the rest in decimal places with 10^... I can't see the exponents in your question and it's late here. Good luck! For instance, 6.434*10^3 ... I recall it takes about 5 hours, so you should get there, so about 5 * 3600 = 18000 seconds. Nice!
