Grace starts with 100 milligrams of a radioactive substance. the amount of thesubstance decreases by each week for a number of weeks, w. she writes theexpression 1000y" to find the amount of radioactive substance remaining atter wweeksryan starts with 1 milligram of a radioactive substance. the amount of the substancedecreases by 40% each week for a number of weeks, w. he writes the expression (1 -oa) to find the amount of radioactive substance remaining after w weeks, use the drop down menus to explain what each part of grace's and ryan'sexpressions mean, nony