Practice!

Sample Problem

Let M represent the mass of radioactive Momomium (an imaginary element) in grams,

whose half-life is 16,100 years. The quantity of Momomium present after t years is

M(t)=18(1/2)t/16,100. Answer the following questions.

a)What is the initial quantity of Momomium? (round to the nearest whole gram)

grams

b)What is the quantity of Momomium present after 20,000 years? (round to the nearest tenth of a gram)

grams

Solution

a)M(t)=18(1/2)t/16,100

Initial quantity, when t=0; M(0)=18(1/2)0=18 grams

b)M(20,000)=18(1/2)20,000/16,100=7.6089≈7.6 grams