Help on math homework

Asap (explain how you got it as well for brainliest)i tried 1: 2 and 2: 3 and they were wrong.picture of figure: in the figure below, the segment is parallel to one side of the triangle. the ratio of 12 to y is1: 21: 31: 42: 3

Find the quotient with the restriction.

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.