A certain element has a half-life of 120 years. After a certain sample of that element was stored for 600 years, only 7 grams was left. How many grams were in the original sample?
600 is 5 half lifes 7 14 28 56 112 224 gm
Amount of original sample =A
7 = A x 1/2^(600/120)
7 = A x 1/2^(5)
7 = A x 0.03125
A = 7 / 0.03125
A = 224 grams the original amount of the sample.
+1072 
