I need help with question 30

TALS He 4.0 ID: A Name: Problem 28. Strontium-90 undergoes beta decay and has a half-life of 28 years. a) Write the nuclear equation for the beta decay of strontium-90. b) Determine the amount of strontium-90 that would remain 112 years from now if you began with 80 g today. c) What will the daughter-to-parent mass ratio be after 112 years? 29. Iodine-131 has a half-life of 8 days. Assume you began with 10.0 g of iodine-131 today. On the following set of axes, sketch a decay curve for iodine-131 representing a 56-day time period. Label clearly on the graph the amount of iodine-131 remaining after 40 days. 3 . 5 Mass of 1. 25. 2.5 lodine-131 Remaining (90.6- 1.25 110:3 0.5 4 8 16:24 32 4.0 48 56 Elapsed Time (day's) . 30. An ancient burial site has been discovered, and radiocarbon dating is being employed to date the human remains found in the graves. If the amount of carbon-14 remaining in one of the bones fou at the site is determined to be . (1.56 percent) of the amount present in living bone material. approximately how long ago did this individual die