How do I do Unit Analysis. Chemistry?

Question

Example-A plane is flying at an altitude of 30,000 feet. How high is it in kilometers. Help ME

Answer 1

30,000 ft.
5280 ft = 1 mi, thus 30,000 ft = 5.682 mi
1 mi = 1.609 km, thus 5.682 mi = 9.144 km.