Calcium-51 has a half-life of 4.5 days. Only 0.75 gram remains of a sample that was initially 12 grams. How old is the sample of calcium-51? 4.5 days 9.0 days 13.5 days 18 days
12 grams.divided by 2= 6 grams divided by 2=3 gramsdivided by 2= 1.5 gramsdivided by 2= 0.75 gram 4 times it is being halfed4.5 day it takes to lose the half So, (4 x 4.5 days) = 18 days . Read
