I need the expression that represents the length of the pool

You are a clerk at convenience store. a customer owes 11.69 for a bag of potatoes chips. she gives you a five dollar bill. how much change should the customer receive?

Roger could feed 5 walruses with 4 kilograms of fish. how many walruses could he feed with 7.2 kilograms of fish?

How many times larger is 9 × 10^8 than 3 × 10^-5? a. 3 × 10^13 b. 3 × 10^-40 c. 3 × 10^-13 d. 3 × 10^3