Eve, an eavesdropper, wants to capture as much communication traffic as possible. She can eavesdrop on a specific channel for at most two hours, contiguously or otherwise, or she will be detected. There are ten channels for her to choose from and she can eavesdrop for a total of 10 hours. Each channel cycles its transmission, but Eve will learn nothing by capturing the same traffic twice.

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.