Carolina is mowing lawns for a summer job. for every mowing job, she charges an initial fee plus $6 sign, for each hour of work. her total fee for a 4-hour job, for instance, is $32. let f(t), denote carolina's fee for a single job f (measured in dollars) as a function of the number of hours t it took her to complete it. write the function's formula.

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?