Amarketing firm is studying consumer preferences for winter fashions. from a population of women aged 18 to 21 years, a random sample of 100 women was selected in the month of january. three more similar random samples were conducted during the months of march, june, and september. what is the number of samples?

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.