A large coffee urn dispenses coffee at a hospital cafeteria. The cafeteria is open from 6 am until 7 pm daily. The rate at which coffee is added to the urn is modeled by the function e(x)=2x^3+7, where the rate is measured in cups of coffee per hour since the cafeteria opened. The rate at which coffee is dispensed from the urn is modeled by the function l(x)=5x^2+10, where the rate is measured in cups of coffee per hour since the cafeteria opened. What does (e - l)(4) mean in this situation?
a) The rate at which the number of cups of coffee in the urn is changing 4 hours after the cafeteria opened is 122 cups per hour.
b)The rate at which the number of cups of coffee in the urn is changing 4 hours after the cafeteria opened is 45 cups per hour
c)There are 45 cups of coffee in the urn 4 hours after the cafeteria opened.
d)There are 122 cups of coffee in the urn 4 hours after the cafeteria opened.
