In October 2005, a family's gasoline consumption is 35 gallons per month and is increasing at a rate of 2.5 gallons per month.
The price of gasoline is 300 cents per gallon and is increasing at a rate of 10 cents per month.
Calculate the rate at which the family's monthly gasoline bill is increasing at this time. Give your answer correct to the nearest cent per month.
Hint: write the family's monthly gasoline consumption as the function f (t) and the price of gasoline as the function g (t). What is the family's monthly gasoline bill in terms of the functions f and g?