Please help with exponential investment problem! I can't figure it out for the life of me and my teacher is never any help

What is the rate for one gallon of gasoline

Arestaurant offers delivery for their pizzas. the total cost the customer pays is the price of the pizzas, plus a delivery fee. one customer pays $23 to have 2 pizzas delivered. another customer pays $59 for 6 pizzas. how many pizzas are delivered to a customer who pays $86?

The relative growth rate for a certain type of fungi is 60% per hour.a small culture has formed and in just 6 hours the count shows to be 20,273 fungi in the culture.what is the initial number of fungi in the culture?