Strontium-90 is a radioactive material that decays according to the function A(t) = A0? 0'024'\

- 0.0244t Strontium-90 is a radioactive material that decays according to the function A(t) = Aoe where Ao is the initial amount present and A is the amount present at time t (in years). Assume that a scientist has a sample of 400 grams of strontium-90. (a) What is the decay rate of strontium-90? (b) How much strontium-90 is left after 40 years? (c) When will only 100 grams of strontium-90 be left? (d) What is the half-life of strontium-90?