Consider 2 ¼ divided by 1/4 (a) Write a real-world problem for the division.
(b) Create a model or write an equation for the division.
(c) Find the quotient for the real-world problem in part (a). Show your work or explain your reasoning.

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.