Try another version of this question An unknown radioactive element decays into non-radioactive substances. In ` 920` days the radioactivity of a sample decreases by `39` percent. (a) What is the half-life of the element?
(days) (b) How long will it take for a sample of `100` mg to decay to `99` mg?
(days) Box 1: Enter your answer as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 2^3, 5+4) Box 2: Enter your answer as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 2^3, 5+4)
Enter DNE for Does Not Exist, oo for Infinity 1290.1075285648
Enter DNE for Does Not Exist, oo for Infinity 18.706004024619