Andrea's family stopped at the gas station to get gas. at gas stations, the price of gas per gallon is given to the nearest thousandth. in order to determine how much money he would need to pay for the gas, andrea's dad asked her to round the price of gas per gallon to the nearest hundredth. the gas price per gallon rounded to the nearest hundredth was $2.50. which of the following prices could have been the original gas price?

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.