Pls ! which number sentence is not true?

Aiden buys two bags of chips at $1.09 each and a 20 ounce soda for $1.20 at the gas station.he knows that the state tax is 5.5. how much change will he receive from a $5 bill?

What is the definition of exponential decay?

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50.