The amount of tears in the room (denoted by ttt) can be defined as a function of the number of people present in the room (denoted by ppp), the number of chopped onions in the room (denoted by ooo), and the deliciousness of the onions (denoted by ddd) using this formula: t =3\cdot \dfrac{p\cdot o^3}{d^2}t=3⋅ d 2 p⋅o 3 t, equals, 3, dot, start fraction, p, dot, o, start superscript, 3, end superscript, divided by, d, start superscript, 2, end superscript, end fraction select an appropriate measurement unit for amount of tears in a room.

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.