The cost, C, of a house is given by the function C(O), where t is the number of years since 1998 and C is measured in thousands of dollars. Which equation indicates that the house had a value of $300,000 in 2008?

The volume of a spherical hot air balloon v(r) = 4 3 ? r3 changes as its radius changes. the radius is a function of time given by r(t) = 3t. find the instantaneous rate of change of the volume with respect to t at t = 2.