1) In a half life decay process, start with 3.98 mCi of material having a half-life of 40 mins. How many mCi of this isotope would be remaining after 4 hours and 12 mins?
2) In a half-life decay process, start with 4.00 mCi of material having a half life of 25 mins. Without any detailed calculations, approximately how many mCi of this isotope would be remaining after 2 hours and 10 mins?