The flywheel on a steam engine rotates 60 revolutions every 15 seconds. What is the flywheel’s rate of revolutions per second? ( can somebody tell me what the unit rate and the rate unit is)

Kapil needed to buy a long wooden beam. he went to two sawmills that each charge an initial fee plus an additional fee for each meter of wood. the following equation gives the price (in dollars) of a wooden beam from the first sawmill as a function of its length (in meters). p = 5+20xp=5+20x