Answer:
Learn from their experiment and know the possible results from trial and error
It is important to use low flame when evaporating water from a recovered filtrate because then the water and filtrate will not spatter and the filtrate can also be recovered after evaporating water.
If flame is not low then water as well as got spatter so it is important to use low flame so that the water and filtrate will not spatter.
Each half life is 1/2 of original amount, so this would take 3 half-lives because (1/2 * 1/2 * 1/2 = 1/8)
Total time = 24,300 * 3 = 72,900 years
