t'x mathxl.com v-w-u-u-ww-M' Spring17 MAT 143-40 k Score: 0 of 1 pt 4 x 11 of 11 (9 complete) v , HW Score: 68.07%, 7.4901'11 gi V is Question Help A toxic radioactive substance with a density of 2 milligrams per square centimeter is detected in the ventilating ducts of a nuclear processing building that was used 45 years ago. if the haif- life of the substance is 20 years, what was the density of the substance when it was deposited 45 years ago? The density of the radioactive substance when it was deposited 45 years ago was approximately D mg / cm2. (Round to the nearest tenth as needed.) r tm with "any :;i in"; in answer box and then click Check