Hunter, a meteorologist, keeps track of the amount of rain each year relative to the amount of rain in 1900. Two
years of data are shown in the table below.

p

step-by-step explanation:

2

step-by-step explanation:

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

source:  

all of the measures need to be converted to the same measure; such as inches. if you do that it is easy to determine which is the longest, 2500 mm which is approximately 97.5 inches.