Susan and Kelvin each receive $100 as a gift. Part A
Susan buys a movie ticket for $11.25 and 4 buckets of popcorn that cost $15.25 each with
her $100. Which statement is true?
Susan has $27.75 of the $100 left over because 100-11.25-(4x15.25)=27.75
Susan has $69.50 of the $100 left over because 100-11.25-4-15.25=69.50
Susan has $39.25 of the $100 left over because 100-15.25-(4x11.25)=39.75
Susan has $73.50 of the $100 left over because 100-11.25-15.25=73.5

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.