Strontium-90 is a radioactive material that decays according to the function Upper A left parenthesis t right parenthesis equals Upper A 0 e Superscript negative 0.0244 t Baseline comma where Upper A 0 is the initial amount present and A is the amount present at time t (in years). Assume that a scientist has a sample of 800 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 600 grams of strontium-90 be left? (d) What is the half-life of strontium-90? Question content area bottom Part 1 (a) The decay rate of strontium-90 is enter your response here%. (Type an integer or a decimal. Include the negative sign for the decay rate.) Part 2 (b) Approximately enter your response here grams of strontium-90 is left after 40 years. (Do not round until the final answer. Then round to the nearest whole number as needed.) Part 3 (c) Only 600 grams of strontium-90 will be left in about enter your response here years. (Do not round until the final answer. Then round to the nearest tenth as needed.) Part 4 (d) The half-life of strontium-90 is approximately enter your response here years. (Do not round until the final answer. Then round to the nearest tenth as needed.)