The function f(h)=m(1/2)^h gives the mass, m, of a radioactive substance remaining after h half-lives. iron has a half-life of 2.7 years. which equation gives the mass of a 200 mg iron sample remaining after y years, and approximately how many milligrams remain after 12 years? 1: f(x) = 2.7(0.5)200; 1.7 mg 2: f(x) = 200(0.5)12; 30.8 mg 3: f(x) = 200(0.5)12; 30.8 mg 4: f(x) = 200(0.185)12; 3.2 mg 5: f(x) = 200(0.774)12; 9.2 mg

If a certain initial amount, A₀, of material decays with a half-life of h, the amount of material that remains at time t is given by the exponential decay model



==================================================
Part (a)
Which equation gives the mass of a 200 mg Iron sample remaining after y years?

∴ A₀ = 200 mg , t = y  and   h = 2.7 years
so, the equation will be:

∴

====================================================

Part (b):
How many milligrams remain after 12 years?


By substitute with y = 12 in the equation obtained from (a)
∴

So, the correct answer is option ⇒ 5: f(x) = 200(0.774)^12; 9.2 mg

Do the math. she originally had 50 dollars on her gift card and she had 12 dollars left on her gift card after she finished her shopping spree. if you subtract 50 minus 12 you get thirty eight dollars as your answer. so therefore, ciara spent 38 dollars total o