Kwei-twang kuo plans to make these online payments: store charge account $160; charitable donation, $40; rent $550; cable bill, $42.01. she began the day with a checking account balance of $16.83. later that same day she estimated her online payments and transferred $800 into checking from savings to cover the expected payments. what will be the balance of her checking account after the online payments are made?

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.