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**Babs0201** In October 2005, a family's gasoline consumption is 20 gallons per month and is increasing at a rate of 0.5 gallons per month. The price of gasoline is 270 cents per gallon and is increasing at a rate of 20 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.

Rate of increase =_________cents per month.

I know that the family's monthly gasoline consumption is the function f (*t*) and the price of gasoline as the function g (*t*). do I try to find the derivatives or anti derivatives?