xiu and jon take the tram from the base camp to the mountain summit. Atfer about six and half minutes in the tram, Jon say"cool! We are a mile above sea level." Xiu says, "we passed the one-mile mark ancouple minutes ago"

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.