Answer:
470 years
Explanation:
.87km(1x10^12nm/1 km)(1s/59nm)(1 min/60s)(1hr/60min)(1day/24hrs)(1yr/365days)
.87 multiplied by 1x10^12
Previous answer divided by 59
Previous answer divided by 60
Previous answer divided by 60
Previous answer divided by 24
Previous answer divided by 365
Final answer is 470 years
Answer is then rouded to two significant figures because the .87 km is only two significant figures
Using these conversion factors each unit would cancel out until you get to years.