The half-life of cesium-137 is 30 years. Suppose we have a 140 mg sample. (a) Find the mass (in mg) that remains after 1\" years. (b) How much of the sample (in mg) remains after 130 years? (Round your answer to two decimal places.) |:|mg (c) After how many years will only 1 mg remain? (Round your answer to one decimal place.) t=|:|vr Suppose a sample of a certain substance decayed to 73.2% of its original amount after 300 days. (Round your answers to two decimal places.) (a) What is the half-life (in days) of this substance? days (b) How long would it take the sample to decay to one-third of its original amount? days