de_middle SG he's bringing his laptop to the exams & when he has a question, just ask here & VIOLA......the answers will appear
peeehead SG 12 years divide by 4 years to get 3 half-lives. 320 > 160 > 80 > 40 *each > represents 1 half life. so there's 40g left.
SilverRevo SG why do I see area of circle and summation equations .. diao ... 12 years / 4 is 3 halflife 1/2^3 x 320. 40g lor ... 1 mark question at O levels.
