Application problem with a linear function:... Espaol The monthly cost (in dollars) of water use is a linear function of the amount of water used (in hundreds of cubic feet, HCF). The cost for using 13 HCF of water is $36.20, and the cost for using 30 HCF is $65.95, What is the cost for using 19 HCF of water? Monthly cost (in dollars) Water usage (in HCF) $0 X ? 2 ER