Which of the following circumstances describes a proportional relationship?
Water flows from a hose into an empty 10 gallon bucket at a rate of 2 gallons per minute.
plumber is paid $50 per hour plus a $75 service charge.
The cost of renting a car is $45 for the first day and $20 per day for each additional day.
A student has $100 in a savings account and saves $5 per month for the next twelve months.